Herbivorous dinosaur jaw disparity and its relationship to extrinsic evolutionary drivers.
Herbivorous dinosaur jaw disparity and its relationship to extrinsic evolutionary drivers.
复制标题
草食性恐龙颌骨差异及其与外部进化驱动因素的关系。
DOI：
10.1017/pab.2016.31
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发表时间：
2017-02
期刊：
影响因子：
2.7
通讯作者：
Rayfield EJ
中科院分区：
文献类型：
--
作者：
MacLaren JA;Anderson PS;Barrett PM;Rayfield EJ
非哺乳动物的草食动物的外部生态驱动程序的形态学反应还没有被量化在较长的时间尺度。食草非鸟类恐龙是测试这种反应的理想群体，因为它们统治陆地生态系统超过1.55亿年，包括有史以来最大的食草动物。恐龙的辐射被几个生态上重要的事件打断，包括三叠纪/侏罗纪（Tr/J）和侏罗纪/白垩纪（J/K）边界的灭绝，苏铁植物的衰落和被子植物的起源，所有这些都可能对草食动物群落产生深远的影响。在这里，我们提出了第一次分析的形态和生物力学差异的蜥脚类和鸟臀目恐龙，以调查模式的颌骨形状和功能，随着时间的推移。我们发现，形态和生物力学下颌差异解耦：下颌骨形状差异遵循分类多样性，通过中生代稳步增加。相比之下，生物力学差异在晚侏罗世达到顶峰，这与蜥脚类动物之间功能变化的增加相对应。生物力学差异的减少与J/K灭绝、蜥脚类和剑龙多样性的丧失以及苏铁植物的减少相吻合。我们没有发现生物力学差异和被子植物的增殖之间的具体对应关系。在白垩纪的大部分时间里，已经存在的分类群在生态和功能上的不断更替导致了差异模式，除了几个独特的类群，比如鹦鹉龙科，它们的生物力学或形态学特征从未被取代。
Morphological responses of nonmammalian herbivores to external ecological drivers have not been quantified over extended timescales. Herbivorous nonavian dinosaurs are an ideal group to test for such responses, because they dominated terrestrial ecosystems for more than 155 Myr and included the largest herbivores that ever existed. The radiation of dinosaurs was punctuated by several ecologically important events, including extinctions at the Triassic/Jurassic (Tr/J) and Jurassic/Cretaceous (J/K) boundaries, the decline of cycadophytes, and the origin of angiosperms, all of which may have had profound consequences for herbivore communities. Here we present the first analysis of morphological and biomechanical disparity for sauropodomorph and ornithischian dinosaurs in order to investigate patterns of jaw shape and function through time. We find that morphological and biomechanical mandibular disparity are decoupled: mandibular shape disparity follows taxonomic diversity, with a steady increase through the Mesozoic. By contrast, biomechanical disparity builds to a peak in the Late Jurassic that corresponds to increased functional variation among sauropods. The reduction in biomechanical disparity following this peak coincides with the J/K extinction, the associated loss of sauropod and stegosaur diversity, and the decline of cycadophytes. We find no specific correspondence between biomechanical disparity and the proliferation of angiosperms. Continual ecological and functional replacement of pre-existing taxa accounts for disparity patterns through much of the Cretaceous, with the exception of several unique groups, such as psittacosaurids that are never replaced in their biomechanical or morphological profiles.