The amphi‐boreal faunal element comprises closely related species and conspecific populations with vicarious distributions in the North Atlantic and North Pacific basins. It originated from an initial trans‐Arctic dispersal in the Pliocene after the first opening of the Bering Strait, and subsequent inter‐oceanic vicariance through the Pleistocene when the passage through the Arctic was severed by glaciations and low sea levels. Opportunities for further trans‐Arctic dispersal have risen at times, however, and molecular data now expose more complex patterns of inter‐oceanic affinities and dispersal histories. For a general view on the trans‐Arctic dynamics and of the roles of potential dispersal–vicariance cycles in generating systematic diversity, we produced new phylogeographic data sets for amphi‐boreal taxa in 21 genera of invertebrates and vertebrates, and combined them with similar published data sets of mitochondrial coding gene variation, adding up to 89 inter‐oceanic comparisons involving molluscs, crustaceans, echinoderms, polychaetes, fishes and mammals. Only 39% of the cases correspond to a simple history of Pliocene divergence; in most taxonomical groups, the range of divergence estimates implies connections through the entire Pliocene–Pleistocene–Holocene time frame. Repeated inter‐oceanic exchange was inferred for 23 taxa, and the latest connection was usually post‐glacial. Such repeated invasions have usually led to secondary contacts and occasionally to widespread hybridization between the different invasion waves. Late‐ or post‐glacial exchange was inferred in 46% of the taxa, stressing the importance of the relatively recent invasions to the current diversity in the North Atlantic. Individual taxa also showed complex idiosyncratic patterns and histories, and several instances of cryptic speciation were recognized. In contrast to a simple inter‐oceanic vicariance scenario underlying amphi‐boreal speciation, the data expose complex patterns of reinvasion and reticulation that complicate the interpretation of taxon boundaries in the region.

中文翻译：

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跨北极扩散和替代的循环，以及两栖海洋动物群的多样化

两栖动物区系包括密切相关的物种和同种种群，它们在北大西洋和北太平洋盆地具有替代分布。它起源于白令海峡首次开放后上新世的最初跨北极扩散，以及随后的更新世穿越北极的通道被冰川和低海平面切断时的跨洋迁移。然而，进一步跨北极扩散的机会有时会增加，分子数据现在揭示了更复杂的海洋间亲缘关系和扩散历史模式。对于跨北极动态以及潜在的扩散 - 替代循环在产生系统多样性方面的作用的一般看法，我们为 21 个无脊椎动物和脊椎动物属的两栖类群生成了新的系统地理学数据集，并将它们与类似的已发表的线粒体编码基因变异数据集相结合，总共进行了 89 次海洋间比较，涉及软体动物、甲壳类动物、棘皮动物、多毛类动物、鱼类和哺乳动物。只有 39% 的病例对应上新世分化的简单历史；在大多数分类群中，差异估计的范围意味着整个上新世-更新世-全新世时间范围内的联系。推断出 23 个类群有重复的海洋间交换，最近的连接通常是冰河后的。这种反复入侵通常会导致二次接触，偶尔还会导致不同入侵波之间的广泛混合。在 46% 的分类群中推断出晚冰期或后冰河交换，强调了相对较新的入侵对北大西洋当前多样性的重要性。个别分类群也显示出复杂的特质模式和历史，并识别出几个神秘物种形成的实例。与基于两栖物种形成的简单的大洋间替代情景相比，这些数据揭示了复杂的再入侵和网状结构模式，这使得对该地区分类群边界的解释变得复杂。