Quaternary glaciations severely altered landscape/seascape at high latitudes and had major consequences on species geographical ranges, population sizes, genetic differentiation and speciation rates. The Magellan province in southern South America, constitutes an interesting area to evaluate the effect of glaciations over near-shore marine benthic organisms. Existing data have showed clear signatures of population genetic bottlenecks during glacial maxima followed by recent recolonizations and expansions during the interglacial. Here, we present new population-based analyses in species of the patellogastropod genus Nacella (N. deaurata, N. magellanica, and N. mytilina). The species N. magellanica and N. deaurata inhabit rocky ecosystems while N. mytilina lives closely associated with kelps. The analyzed species exhibit narrow bathymetric ranges and consequently should have been severely affected by recurrent glacial cycles. We performed phylogeographic and demographic analyses in Nacella species including different localities across their respective distributions in the Magellan province including the Falkland/Malvinas Islands (F/M). Genetic analyses showed that all Nacella species exhibited low levels of genetic diversity, the presence of single dominant broadly distributed haplotypes, lack of correlation between geographical and genetic distance, and recent demographic growths, which are evidence supporting rapid postglacial expansions. Such results may have been facilitated by larval and/or rafting-mediated dispersal following the Cape Horn Current System. The three species showed strong and significant differentiation between F/M and southern Pacific margin (SPM) populations including localities across the Strait of Magellan and Cape Horn. Haplotype genealogies and mismatch analyses recognized older and more complex demographic histories in the F/M than in South America. Different glaciological histories between SPM and F/M may be responsible of the marked phylogeographic structure in the analyzed species of Nacella. Alternatively, as previously proposed, the F/M represent a glacial refugium for Nacella species (sink area), as well as a secondary contact zone where endemic haplotypes are found together with recently arrived South American ones. Historical and contemporary processes, contrasting glacial histories between the analyzed areas, as well as life history traits of the analyzed organisms are main factors explaining current phylogeographic patterns of shallow Magellan marine benthic organisms.

中文翻译：

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南美洲南部麦哲伦省三种 Nacella（Patellogastropoda：Nacellidae）物种种群多样性和结构模式的第四纪冰川循环的遗传足迹

第四纪冰川作用严重改变了高纬度地区的景观/海景，并对物种地理范围、种群规模、遗传分化和物种形成率产生了重大影响。南美洲南部的麦哲伦省构成了一个有趣的区域，用于评估冰川作用对近岸海洋底栖生物的影响。现有数据显示，冰川盛期人口遗传瓶颈的明显特征随后是间冰期最近的重新殖民化和扩张。在这里，我们提出了对髌腹足类物种的新的基于种群的分析机舱(南山猪笼草,麦哲伦猪笼草， 和N. mytilina). 物种麦哲伦猪笼草和南山猪笼草居住在岩石生态系统中，同时N. mytilina生活与海带密切相关。分析的物种表现出狭窄的测深范围，因此应该受到反复出现的冰川周期的严重影响。我们在机舱物种包括麦哲伦省各自分布的不同地点，包括福克兰/马尔维纳斯群岛 (F/M)。遗传分析表明，所有机舱物种表现出低水平的遗传多样性，存在单一的显性广泛分布的单倍型，地理和遗传距离之间缺乏相关性，以及最近的人口增长，这些都是支持冰期后快速扩张的证据。在合恩角洋流系统之后，幼虫和/或漂流介导的扩散可能促进了这种结果。这三个物种在 F/M 和南太平洋边缘 (SPM) 种群之间表现出强烈而显着的差异，包括麦哲伦海峡和合恩角对面的地区。单倍型谱系和错配分析认识到 F/M 的人口历史比南美洲更古老、更复杂。SPM 和 F/M 之间不同的冰川历史可能是所分析物种中显着的系统地理学结构的原因。机舱. 或者，如前所述，F/M 代表冰川避难所机舱物种（汇区），以及次级接触区，在这里发现地方性单倍型与最近到达的南美洲单倍型。历史和当代过程、分析区域之间的对比冰川历史以及所分析生物的生活史特征是解释浅层麦哲伦海洋底栖生物当前系统地理学模式的主要因素。