Hernández-Hernández Tania, Brown Joseph W, Schlumpberger Boris O, Eguiarte Luis E, Magallón Susana
Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, 3er Circuito de Ciudad Universitaria, Del. Coyoacán, México D.F, 04510, México.
Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University Avenue, Ann Arbor, MI, 48109-1048, USA.
New Phytol. 2014 Jun;202(4):1382-1397. doi: 10.1111/nph.12752. Epub 2014 Mar 10.
Succulent plants are widely distributed, reaching their highest diversity in arid and semi-arid regions. Their origin and diversification is thought to be associated with a global expansion of aridity. We test this hypothesis by investigating the tempo and pattern of Cactaceae diversification. Our results contribute to the understanding of the evolution of New World Succulent Biomes. We use the most taxonomically complete dataset currently available for Cactaceae. We estimate divergence times and utilize Bayesian and maximum likelihood methods that account for nonrandom taxonomic sampling, possible extinction scenarios and phylogenetic uncertainty to analyze diversification rates, and evolution of growth form and pollination syndrome. Cactaceae originated shortly after the Eocene-Oligocene global drop in CO2 , and radiation of its richest genera coincided with the expansion of aridity in North America during the late Miocene. A significant correlation between growth form and pollination syndrome was found, as well as a clear state dependence between diversification rate, and pollination and growth-form evolution. This study suggests a complex picture underlying the diversification of Cactaceae. It not only responded to the availability of new niches resulting from aridification, but also to the correlated evolution of novel growth forms and reproductive strategies.
多肉植物分布广泛，在干旱和半干旱地区具有最高的多样性。它们的起源和多样化被认为与全球干旱的扩张有关。我们通过研究仙人掌科多样化的节奏和模式来检验这一假设。我们的结果有助于理解新大陆多肉生物群落的进化。我们使用目前可获得的关于仙人掌科分类最完整的数据集。我们估计分歧时间，并利用考虑非随机分类抽样、可能的灭绝情况和系统发育不确定性的贝叶斯和最大似然方法来分析多样化速率、生长形式和传粉综合征的进化。仙人掌科起源于始新世 - 渐新世全球二氧化碳下降之后不久，其最丰富属的辐射与中新世晚期北美干旱的扩张相吻合。我们发现生长形式和传粉综合征之间存在显著相关性，以及多样化速率与传粉和生长形式进化之间存在明显的状态依赖性。这项研究表明仙人掌科多样化背后存在复杂的情况。它不仅对干旱化导致的新生态位的可用性做出反应，还对新生长形式和繁殖策略的协同进化做出反应。
