Diversity and morphological evolution of Jurassic belemnites from South Germany
Diversity and morphological evolution of Jurassic belemnites from South Germany
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DOI：
10.1016/j.palaeo.2016.05.029
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发表时间：
2016-09-01
影响因子：
3
通讯作者：
De Baets, Kenneth
中科院分区：
文献类型：
--
作者：
Dera, Guillaume;Toumoulin, Agathe;De Baets, Kenneth
箭石是已灭绝的头足类动物，其进化史代表了中生代成功的适应性辐射。然而，仍然缺乏对这种演化的动力学和古环境驱动因素的详细了解。为了填补这一空白，我们分析了德国南部侏罗纪嘴部的多样性和形态差异，并将这些模式与其他欧洲-北方趋势进行了比较。我们发现，在赫坦阶辛穆阶期早期出现了几个不同的类群之后，箭石经历了四个多样化时期（即早期普林斯巴阶、中晚期托阿尔阶、早期巴约阶和牛津阶），其特征是喙部的形态差异，朝向可能针对不同流体动力学特性进行优化的形式。这些适应性辐射在区域范围内被与形态瓶颈相对应的四种生物危机（即普林斯巴赫期托阿尔期、阿伦期、晚巴约期和奇莫里期）中断。其中大多数都是形态选择性的，除了阿伦灭绝，这可能与海平面的显着下降有关。通过将我们的结果与古环境数据进行比较，我们发现暖温带海水温度可能有利于箭石的多样化，从长远来看，可能会加速它们的代谢率、种群更替和进化率。相反，变冷或高温事件则与生物危机相对应。向北极和地中海地区避难区的移民可能是危机后快速恢复的关键因素。最后，现有数据表明，整个侏罗纪讲台呈现出日益精简的趋势。 (C) 2016 Elsevier B.V. 保留所有权利。
Belemnites are extinct cephalopods whose evolutionary history is representative of successful adaptive radiations during the Mesozoic. Nevertheless, a detailed understanding of the dynamics and palaeoenvironmental drivers of this evolution is still lacking. In order to fill this gap, we analyze the diversity and morphological disparity of Jurassic rostra from South Germany, and compare these patterns with other Euro-Boreal trends. We show that, after an early apparition of few dissimilar groups during the Hettangian Sinemurian interval, belemnites experienced four periods of diversification (i.e., Early Pliensbachian, Middle Late Toarcian, Early Bajocian, and Oxfordian) marked by morphological disparifications of rostra towards forms potentially optimized for different hydrodynamic properties. These adaptive radiations were interrupted at regional scale by four biological crises corresponding to morphological bottlenecks (i.e., Pliensbachian Toarcian, Aalenian, Late Bajocian, and Kimmeridgian). Most of them were morphoselective, except the Aalenian extinction, which could be related to a prominent sea level fall. By comparing our results to palaeoenvironmental data, we show that warm temperate seawater temperatures might have favoured the diversification of belemnites, potentially by accelerating their metabolic rates, the population turnovers, and the evolutionary rates on the long term. Conversely, cooling or hyperthermal events correspond with biological crises. Migrations towards refuge areas located in the Arctic and Mediterranean domains could have been key factors for rapid post-crisis recoveries. Finally, the available data suggest a trend towards increased streamlining of the rostrum through the Jurassic. (C) 2016 Elsevier B.V. All rights reserved.