Traditionally focused on Amazonian and Atlantic rainforests, studies on the origins of high Neotropical biodiversity have recently shifted to also investigate biodiversity processes in the South American dry diagonal, encompassing Chaco, Cerrado savannas, and Caatinga seasonally dry tropical forests. The plateau/depression hypothesis states that riparian forests in the Brazilian Shield in central Brazil are inhabited by Pleistocene lineages, with shallow divergences and signatures of population expansion. Moreover, riparian forests may have acted as a vegetation network in the Pleistocene, allowing gene/species flow across the South American dry diagonal. We tested these hypotheses using Colobosaura modesta, a small gymnophthalmid lizard from forested habitats in the Cerrado savannas and montane/submontane forests in the Caatinga. We conducted phylogeographic analyses using a multi‐locus dataset, tested alternative demographic scenarios with Approximate Bayesian Computation, and also employed species delimitation tests. We recovered a history of recent colonization and expansion along riparian forests, associated with Pleistocene climate shifts, and the existence of a new species of Colobosaura restricted to the Serra do Cachimbo region. We also present evidence that riparian forests have provided an interconnected network for forest organisms within the South American dry diagonal and that Pleistocene events played an important role in their evolutionary history.

中文翻译：

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小蜥蜴系统地理学支持的南美干旱对角线内中生森林的更新世扩张和连通性

传统上专注于亚马逊和大西洋雨林，对新热带高度生物多样性起源的研究最近已转向研究南美干旱对角线上的生物多样性过程，包括查科、塞拉多稀树草原和卡廷加季节性干旱的热带森林。高原/洼地假说指出，巴西中部巴西地盾的河岸森林居住着更新世谱系，具有浅的分歧和人口扩张的特征。此外，河岸森林可能在更新世起到了植被网络的作用，允许基因/物种穿过南美干旱对角线。我们使用来自 Cerrado 稀树草原的森林栖息地和卡廷加的山地/亚山地森林的小型裸眼蜥蜴，对这些假设进行了测试。我们使用多位点数据集进行系统地理学分析，使用近似贝叶斯计算测试替代人口统计场景，并使用物种定界测试。我们恢复了最近沿河岸森林殖民和扩张的历史，这与更新世气候变化以及仅限于 Serra do Cachimbo 地区的 Colobosaura 新物种的存在有关。我们还提供证据表明，河岸森林为南美干旱对角线内的森林生物提供了一个相互关联的网络，并且更新世事件在它们的进化历史中发挥了重要作用。我们恢复了最近沿河岸森林殖民和扩张的历史，这与更新世气候变化以及仅限于 Serra do Cachimbo 地区的 Colobosaura 新物种的存在有关。我们还提供证据表明，河岸森林为南美干旱对角线内的森林生物提供了一个相互关联的网络，并且更新世事件在它们的进化历史中发挥了重要作用。我们恢复了最近沿河岸森林殖民和扩张的历史，这与更新世气候变化以及仅限于 Serra do Cachimbo 地区的 Colobosaura 新物种的存在有关。我们还提供证据表明，河岸森林为南美干旱对角线内的森林生物提供了一个相互关联的网络，并且更新世事件在它们的进化历史中发挥了重要作用。