División Ornitología, Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia' (MACN-CONICET), Buenos Aires, Argentina.
Fuller Evolutionary Biology Program, Cornell Laboratory of Ornithology, Ithaca, New York.
Mol Ecol. 2019 Apr;28(7):1730-1747. doi: 10.1111/mec.15018.
Avian diversity in the Neotropics has been traditionally attributed to the effect of vicariant forces promoting speciation in allopatry. Recent studies have shown that phylogeographical patterns shared among codistributed species cannot be explained by a single vicariant event, as species responses to a common barrier depend on the biological attributes of each taxon. The open vegetation corridor (OVC) isolates Amazonia and the Andean forests from the Atlantic Forest, creating a notorious pattern of avian taxa that are disjunctly codistributed in these forests. Here, we studied and compared the evolutionary histories of Ramphotrigon megacephalum and Pipraeidea melanonota, two passerines with allopatric populations east and west of the OVC that represent different subspecies. These species differ in their biological attributes: R. megacephalum is a sedentary, forest specialist mostly confined to bamboo understorey, whereas P. melanonota is a seasonal migrant and generalist species that ranges in a variety of closed and semi-open environments. We performed genetic and genomic analyses, complemented with the study of coloration and behavioural differentiation, to assess population divergence across the OVC. We found that the evolutionary histories of both R. megacephalum and P. melanonota have been shaped by this environmental barrier. However, these species responded in different and asynchronous manners to the establishment of the OVC and to past connections between the currently isolated South American forests, which can be mostly explained by their distinct ecologies and dispersal abilities. Our results support the fact that the biological attributes of species can make their evolutionary histories idiosyncratic.
新热带地区的鸟类多样性传统上归因于隔离导致物种形成的趋异作用。最近的研究表明，在分布区重叠的物种中共享的系统地理格局不能用单一的隔离事件来解释，因为物种对共同屏障的反应取决于每个分类群的生物学特征。开阔植被走廊（OVC）将亚马逊地区和安第斯山脉森林与大西洋森林隔开，形成了一个臭名昭著的鸟类分类群模式，这些鸟类在这些森林中分布不连续。在这里，我们研究并比较了 Ramphotrigon megacephalum 和 Pipraeidea melanonota 的进化历史，这两种雀形目鸟类在 OVC 的东西两侧都有隔离的种群，代表了不同的亚种。这些物种在生物学特征上有所不同：R. megacephalum 是一种定居的、森林特化的物种，主要局限于竹林的下层植被，而 P. melanonota 是一种季节性迁徙的、广泛分布的物种，分布在各种封闭和半开放的环境中。我们进行了遗传和基因组分析，并辅以颜色和行为分化的研究，以评估 OVC 两侧的种群分化。我们发现，R. megacephalum 和 P. melanonota 的进化历史都受到了这种环境障碍的影响。然而，这些物种对 OVC 的建立以及南美森林目前隔离的过去连接以不同的、异步的方式做出了反应，这主要可以用它们不同的生态和扩散能力来解释。我们的研究结果支持了这样一个事实，即物种的生物学特征可以使它们的进化历史变得独特。
