To contribute to what is known about involvement of vegetation dynamics in Neotropical speciation, we used the Epidendrum latilabre complex, a taxonomically well-defined species group, to investigate past connections between Amazonian (AM) and Atlantic (AF) forests and address the following topics: (1) divergence times between sister species currently distributed in AM and AF; (2) distribution patterns of ancestral species of the E. latilabre complex and (3) potential routes connecting ancestral ranges between AM and AF. We developed a robust phylogenetic estimate for species of the E. latilabre complex by sequencing two nuclear and six plastid loci. Then, we combined divergence time estimation, ancestral range reconstruction and ecological niche modelling. Our biogeographic reconstruction exhibits a complex pattern of connections among tropical forests east of the Andes in South America. The AM and AF species of the E. latilabre complex are intermixed in the results, and climatic shifts during the Pleistocene (Chibanian) are suggested here as a major force promoting speciation. Sister species tend to be ecologically distinct in their climate niche spaces, and vicariance and peripheral isolation are reconstructed as the main drivers of speciation. There is evidence to suggest that the south-east/north-west bridge and the northern/north-eastern coastal route have been occupied by the ancestors of the E. latilabre complex, and alternative routes across the South American dry diagonal were unlikely. Further studies on Neotropical epiphytic taxa are still necessary for understanding the dynamics of historical connections between AM and AF.

中文翻译：

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第四纪冰川作用在最近进化的南美附生兰花进化枝中塑造生物地理模式的作用

为了有助于了解植被动力学在新热带物种形成中的参与，我们使用 Epidendrum latilabre complex（一个分类学上定义明确的物种群）来调查亚马逊 (AM) 和大西洋 (AF) 森林之间过去的联系，并解决以下主题：（1）目前分布在 AM 和 AF 的姐妹物种之间的分歧时间；(2) E. latilabre 复合体祖先物种的分布模式和 (3) 连接 AM 和 AF 之间祖先范围的潜在途径。我们通过对两个核和六个质体基因座进行测序，对 E. latilabre 复合体的物种进行了稳健的系统发育估计。然后，我们结合了分歧时间估计、祖先范围重建和生态位建模。我们的生物地理重建展示了南美洲安第斯山脉以东热带森林之间复杂的联系模式。E. latilabre 复合体的 AM 和 AF 物种在结果中混合在一起，并且这里建议更新世（Chibanian）期间的气候变化是促进物种形成的主要力量。姐妹物种在它们的气候生态位空间中往往在生态上是不同的，并且替代和外围隔离被重建为物种形成的主要驱动力。有证据表明东南/西北桥梁和北部/东北沿海路线已被 E. latilabre 复合体的祖先占据，不太可能跨越南美干燥对角线的替代路线。