División Antropología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Consejo Nacional de Investigaciones Científicas y Técnicas, 1900 La Plata, Buenos Aires, Argentina.
École Normale Supérieure, Paris Sciences et Lettres (PSL) Research University, Institut de Biologie de l'École Normale Supérieure (IBENS), CNRS UMR 8197, INSERM U1024, 46 rue d'Ulm, F-75005, Paris, France.
Evolution. 2018 Dec;72(12):2697-2711. doi: 10.1111/evo.13609. Epub 2018 Oct 9.
Understanding the origin of diversity is a fundamental problem in evolutionary biology. The null expectation for the evolutionary diversification is that all changes in biological diversity are the result of random processes. Adaptive radiations depart from this expectation as ecological factors and natural selection are supposed to play a central role in driving exceptional diversification. However, it is not well understood how large-scale continental radiations, given their characteristics, fit to these opposing theoretical models. Here, we used phylogenetic comparative methods and geometric morphometrics to study the evolutionary process of cranial diversification in the continental radiation of New World monkeys. Particularly, we tested several alternative evolutionary scenarios for morphological evolution in the clade. Results indicated that despite the platyrrhine radiation being old and geographically widespread, the formative patterns arising from the initial stages of diversification probably associated with an adaptive radiation can still be recognized today. We also show that no single explored factor (e.g., ecological or allometric) can be invoked as a complete explanation for the observed phenotypic diversity patterns in the clade and, moreover, that different cranial regions exhibit particular macroevolutionary patterns. Together, our results highlight the evident complexity behind large-scale evolutionary radiations.
理解多样性的起源是进化生物学中的一个基本问题。对于生物多样性的进化多样化，零假设是所有的变化都是随机过程的结果。适应辐射偏离了这一预期，因为生态因素和自然选择应该在驱动异常多样化方面发挥核心作用。然而，对于大规模的大陆辐射，其特征如何适应这些相互对立的理论模型，还不是很清楚。在这里，我们使用系统发育比较方法和几何形态计量学来研究新大陆猴大陆辐射中颅部多样化的进化过程。特别是，我们测试了该进化枝中形态进化的几种替代进化情景。结果表明，尽管platyrrhine 辐射已经很古老且地理分布广泛，但从多样化的初始阶段产生的形成模式可能仍然与适应辐射有关。我们还表明，没有任何一个被探索的因素（例如生态或异速生长）可以作为该进化枝中观察到的表型多样性模式的完整解释，此外，不同的颅部区域表现出特定的宏观进化模式。总之，我们的研究结果强调了大规模进化辐射背后明显的复杂性。
