Evidence for a Mid-Jurassic Adaptive Radiation in Mammals
Evidence for a Mid-Jurassic Adaptive Radiation in Mammals
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DOI：
10.1016/j.cub.2015.06.047
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发表时间：
2015-08-17
期刊：
影响因子：
9.2
通讯作者：
Benson, Roger B. J.
中科院分区：
文献类型：
--
作者：
Close, Roger A.;Friedman, Matt;Benson, Roger B. J.
近年来，一系列惊人的发现改变了我们对中生代哺乳动物的理解。这些发现揭示了迄今未被怀疑的生态形态多样性，表明哺乳动物在中晚侏罗世经历了一次重大的适应性辐射[1]。哺乳动物宏观进化的模式必须根据这些新发现重新解释[1-3]，但只有分类多样性和形态差异的有限方面已经量化[4，5]。我们使用离散字符的大数据集的形态演变和时间模式的差距评估率。晚侏罗世之前的形态演化率显着升高，与一个明显的高峰期发生在早中侏罗世。这种表型创新的强烈爆发与表观长期站立多样性的逐步增加[4]和最大差异的实现相吻合，支持早期哺乳动物多样化的“短保险丝”模型[2，3]。之后，这一比率急剧下降，直到中生代末期，甚至在兽亚目动物中，这一比率都保持在相当低的水平。这支持了中生代兽科动物多样化的“长熔丝”模型。我们的研究结果表明，持续的形态创新在三叠纪干组哺乳动物达到高潮，在全球适应辐射冠组成员在早中侏罗世。
A series of spectacular discoveries have transformed our understanding of Mesozoic mammals in recent years. These finds reveal hitherto-unsuspected ecomorphological diversity that suggests that mammals experienced a major adaptive radiation during the Middle to Late Jurassic [1]. Patterns of mammalian macroevolution must be reinterpreted in light of these new discoveries [1-3], but only taxonomic diversity and limited aspects of morphological disparity have been quantified [4, 5]. We assess rates of morphological evolution and temporal patterns of disparity using large datasets of discrete characters. Rates of morphological evolution were significantly elevated prior to the Late Jurassic, with a pronounced peak occurring during the Early to Middle Jurassic. This intense burst of phenotypic innovation coincided with a stepwise increase in apparent long-term standing diversity [4] and the attainment of maximum disparity, supporting a "short-fuse" model of early mammalian diversification [2, 3]. Rates then declined sharply, and remained significantly low until the end of the Mesozoic, even among therians. This supports the "long-fuse" model of diversification in Mesozoic therians. Our findings demonstrate that sustained morphological innovation in Triassic stem-group mammals culminated in a global adaptive radiation of crown-group members during the Early to Middle Jurassic.