Newly arrived species on young or remote islands are likely to encounter less predation and competition than source populations on continental landmasses. The associated ecological release might facilitate divergence and speciation as colonizing lineages fill previously unoccupied niche space. Characterizing the sequence and timing of colonization on islands represents the first step in determining the relative contributions of geographical isolation and ecological factors in lineage diversification. Herein, we use genome-scale data to estimate timing of colonization in Naesiotus snails to the Galápagos islands from mainland South America. We test inter-island patterns of colonization and within-island radiations to understand their contribution to community assembly. Partly contradicting previously published topologies, phylogenetic reconstructions suggest that most Naesiotus species form island-specific clades, with within-island speciation dominating cladogenesis. Galápagos Naesiotus also adhere to the island progression rule, with colonization proceeding from old to young islands and within-island diversification occurring earlier on older islands. Our work provides a framework for evaluating the contribution of colonization and in situ speciation to the diversity of other Galápagos lineages.

中文翻译：

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加拉帕戈斯陆生蜗牛特有辐射中的群岛范围内的殖民化和物种形成模式

与大陆陆地上的来源种群相比，年轻或偏远岛屿上的新到达物种可能会遇到较少的捕食和竞争。相关的生态释放可能会促进分化和物种形成，因为殖民谱系填充了以前未被占用的生态位空间。表征岛屿殖民化的顺序和时间是确定地理隔离和生态因素在谱系多样化中的相对贡献的第一步。在这里，我们使用基因组规模的数据来估计 Naesiotus 蜗牛从南美洲大陆到加拉帕戈斯群岛的殖民时间。我们测试岛间殖民模式和岛内辐射，以了解它们对社区集会的贡献。部分地与之前发布的拓扑相矛盾，系统发育重建表明，大多数 Naesiotus 物种形成岛屿特定的进化枝，岛内物种形成主导进化枝。加拉帕戈斯 Naesiotus 也遵守岛屿进程规则，殖民化从旧岛屿到新岛屿进行，岛内多样化发生在较早的岛屿上。我们的工作提供了一个框架，用于评估殖民化和原位物种形成对其他加拉帕戈斯血统的多样性的贡献。