One of the main goals of evolutionary biology is to understand the processes behind current patterns of biodiversity. Shared geographic distributions among unrelated species may result from a common history, providing a unique opportunity to assess the evolution of the landscape and the origins of biodiversity. Until recently, vicariance prevailed as the main evolutionary model to be tested, and the riverine barrier hypothesis the null model for taxa with river‐bounded distributions. In recent years, however, multispecies comparative approaches have unveiled idiosyncratic scenarios among codistributed species, suggesting that rivers may or may not play a role in the speciation process. In a From the Cover article in this issue of Molecular Ecology , Kopuchian et al. (2020) explore predictions of the riverine barrier hypothesis in a major subtropical river system, evaluating the degree of mitochondrial and nuclear genomic differentiation in seven bird species with allegedly morphological differentiation across the Paraná‐Paraguay river system. The authors show that in only one case, the genetic differentiation was concordant with the river. Interestingly, pairs presented disparate divergence times and/or distinct demographic histories. In most cases, putative contact zones broadly coincided with the transition of different ecoregions, such as the Espinal/Chaco ecological ecotone. These findings argue against the role of the Paraná‐Paraguay river system as a major biogeographic barrier and highlight the need to explore the role of ecology in species diversification. Here, we feature different perspectives for studying the processes governing species divergence and suggest a basic protocol to advance the study of riverine barriers.

中文翻译：

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超越河流屏障的维多利亚式范式。

进化生物学的主要目标之一是了解当前生物多样性模式背后的过程。不相关物种之间共享的地理分布可能来自共同的历史，这为评估景观演变和生物多样性起源提供了独特的机会。直到最近，方差仍是要测试的主要进化模型，而河流屏障假设则是具有河流边界分布的生物分类的零模型。然而，近年来，多物种比较方法揭示了共同分布物种之间的特异情况，这表明河流可能会或可能不会在物种形成过程中发挥作用。在本期《分子生态学》的封面文章中，Kopuchian等。（2020）研究了主要亚热带河流系统中河流屏障假说的预测，评估了巴拉那-巴拉圭河流系统中据称形态分化的七种鸟类的线粒体和核基因组分化程度。作者表明，只有一种情况，遗传分化与河流是一致的。有趣的是，配对呈现出不同的发散时间和/或不同的人口历史。在大多数情况下，推定的接触区与埃斯皮纳尔/查科生态过渡带等不同生态区域的过渡大致吻合。这些发现与巴拉那巴拉圭河系作为主要的生物地理屏​​障的作用相反，并强调了探索生态学在物种多样化中的作用的必要性。这里，