Barriers to dispersal are recognized to play an important role in the differentiation of populations and ultimately in speciation. In the southeast Pacific, on the northern coast of Peru, a transition zone between the Peruvian and Panamic marine biogeographic provinces exists. Here, the convergence between two contrasting surface currents could generate a barrier effect for the larval dispersal of meroplanktonic invertebrates, which could in turn generate differentiated populations or genetic lineages on both sides of the transition zone. To address this, we studied to Echinolittorina paytensis, an abundant rocky intertidal periwinkle that spans both biogeographic provinces. A total of 95 individuals from Ecuador (2°19′S) to central Peru (7°31′S), covering the Panamic Province, the Peruvian Province, and the transition zone between, were collected. The mitochondrial markers cytochrome c oxidase I and 16SrRNA were sequenced in order to investigate phylogeography and genetic structuring. In general, no genetic structuring was found across the transition zone, suggesting this biogeographic boundary would not be acting as a barrier in this species. Factors such as a high larval dispersal capability and the occurrence of El Niño–Southern Oscillation events such as El Niño are discussed.

中文翻译：

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通过东南太平洋生物地理过渡带的潮间带岩石长春花棘皮鱼类的系统地理学

认识到传播障碍在种群分化以及最终在物种形成中起着重要作用。在东南太平洋，在秘鲁北海岸，存在着秘鲁和巴拿马海洋生物地理省之间的过渡区。在这里，两个相反的表面电流之间的会聚可能会产生对浮游无脊椎动物幼虫扩散的屏障效应，这反过来又会在过渡带的两侧产生分化的种群或遗传谱系。为了解决这个问题，我们研究了Echinolittorina paytensis，这是横跨两个生物地理省的丰富的岩石潮间带长春花。从厄瓜多尔（2°19′S）到秘鲁中部（7°31′S）总共收集了95个个体，覆盖了全景省，秘鲁省及其之间的过渡区。线粒体标记细胞色素c氧化酶I和16SrRNA进行了测序，以研究系统地理学和遗传结构。通常，在整个过渡带都没有发现遗传结构，这表明该生物地理边界不会成为该物种的屏障。讨论了诸如高幼虫传播能力和厄尔尼诺现象的发生等因素-厄尔尼诺现象等南方涛动事件。