Nine exceptional radiations plus high turnover explain species diversity in jawed vertebrates
Nine exceptional radiations plus high turnover explain species diversity in jawed vertebrates
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DOI：
10.1073/pnas.0811087106
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发表时间：
2009-08-11
影响因子：
11.1
通讯作者：
Harmon, Luke J.
中科院分区：
文献类型：
--
作者：
Alfaro, Michael E.;Santini, Francesco;Harmon, Luke J.
物种丰富度分布不均是脊椎动物生物多样性的一个基本且无法解释的模式。尽管哺乳动物、鸟类或硬骨鱼类等群体的物种丰富度通常归因于分支形成的加速，但我们缺乏一个定量的概念框架来识别和比较脊椎动物进化史上节奏的异常变化。我们开发了 MEDUSA，这是一种基于 Akaike 信息标准的逐步方法，用于检测未完全解决的系统发育中出生率和死亡率的多重变化。我们不完全地将 MEDUSA 应用于多样性树，总结了 44 个主要有颌脊椎动物分支的进化关系和物种丰富度。我们确定了颚口类动物多样化速度的 9 个主要变化；其中最重要的是一个进化枝的基础，该进化枝包括大多数与珊瑚礁相关的鱼类以及慈鲷和鲈鱼。速率增加也是几种公认的四足动物辐射的基础，包括大多数现代鸟类、蜥蜴和蛇、骨栖鱼类和大多数真兽类哺乳动物。此外，我们发现脊椎动物树的大部分区域表现出几乎相同的起源和灭绝率，这从分子数据中提供了一些初步证据，证明动物群更替在塑造生物多样性方面的重要性。总之，这些结果揭示了现存脊椎动物的生物多样性是波动性更替的产物，其中有 6 次加速和 3 次减速，这 6 次加速导致了所有物种的 85% 以上，而 3 次减速则产生了“活化石”。此外，通过揭示脊椎动物多样化的特殊脉冲的时间以及经历这些脉冲的进化枝，我们的多样性树提供了一个评估脊椎动物辐射的特定因果假设的框架。
The uneven distribution of species richness is a fundamental and unexplained pattern of vertebrate biodiversity. Although species richness in groups like mammals, birds, or teleost fishes is often attributed to accelerated cladogenesis, we lack a quantitative conceptual framework for identifying and comparing the exceptional changes of tempo in vertebrate evolutionary history. We develop MEDUSA, a stepwise approach based upon the Akaike information criterion for detecting multiple shifts in birth and death rates on an incompletely resolved phylogeny. We apply MEDUSA incompletely to a diversity tree summarizing both evolutionary relationships and species richness of 44 major clades of jawed vertebrates. We identify 9 major changes in the tempo of gnathostome diversification; the most significant of these lies at the base of a clade that includes most of the coral-reef associated fishes as well as cichlids and perches. Rate increases also underlie several well recognized tetrapod radiations, including most modern birds, lizards and snakes, ostariophysan fishes, and most eutherian mammals. In addition, we find that large sections of the vertebrate tree exhibit nearly equal rates of origination and extinction, providing some of the first evidence from molecular data for the importance of faunal turnover in shaping biodiversity. Together, these results reveal living vertebrate biodiversity to be the product of volatile turnover punctuated by 6 accelerations responsible for >85% of all species as well as 3 slowdowns that have produced ''living fossils." In addition, by revealing the timing of the exceptional pulses of vertebrate diversification as well as the clades that experience them, our diversity tree provides a framework for evaluating particular causal hypotheses of vertebrate radiations.