Understanding the role of dispersal and adaptation in the evolutionary history of marine species is essential for predicting their response to changing conditions. We analyzed patterns of genetic differentiation in the key tropical calcifying species of large benthic foraminifera Amphistegina lobifera to reveal the evolutionary processes responsible for its biogeographic distribution. We collected specimens from 16 sites encompassing the entire range of the species and analyzed hypervariable fragments of the 18S SSU rDNA marker. We identified six hierarchically organized genotypes with mutually exclusive distribution organized along a longitudinal gradient. The distribution is consistent with diversification occurring in the Indo‐West Pacific (IWP) followed by dispersal toward the periphery. This pattern can be explained by: (a) high dispersal capacity of the species, (b) habitat heterogeneity driving more recent differentiation in the IWP, and (c) ecological‐scale processes such as niche incumbency reinforcing patterns of genotype mutual exclusion. The dispersal potential of this species drives the ongoing range expansion into the Mediterranean Sea, indicating that A. lobifera is able to expand its distribution by tracking increases in temperature. The genetic structure reveals recent diversification and high rate of extinction in the evolutionary history of the clade suggesting a high turnover rate of the diversity at the cryptic level. This diversification dynamic combined with high dispersal potential, allowed the species to maintain a widespread distribution over periods of geological and climatic upheaval. These characteristics are likely to allow the species to modify its geographic range in response to ongoing global warming without requiring genetic differentiation.

中文翻译：

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高分散能力和生物地理学的突破塑造了全球分布的礁石钙化石的遗传多样性。

了解扩散和适应在海洋物种进化史中的作用对于预测其对变化条件的响应至关重要。我们分析了大型底栖有孔虫Amphistegina lobifera的关键热带钙化物种的遗传分化模式。揭示负责其生物地理分布的进化过程。我们从16个地点采集了标本，涵盖了整个物种范围，并分析了18S SSU rDNA标记的高变片段。我们确定了六个分层组织的基因型，它们沿着纵向梯度相互排斥地分布。分布与印度洋-西太平洋（IWP）发生的多样化相一致，然后向外围扩散。这种模式可以通过以下方式解释：（a）物种的高度分散能力；（b）栖息地异质性驱动IWP的近期分化；以及（c）生态规模过程，例如基因型互斥的生态位在位增强模式。lobifera能够通过跟踪温度升高来扩展其分布。遗传结构揭示了进化进化史中最近的多样性和高度灭绝的现象，表明在隐秘水平上多样性的高周转率。这种多样化的动力加上较高的扩散潜力，使该物种在地质和气候动荡时期保持了广泛的分布。这些特征很可能使该物种能够响应不断发生的全球变暖而改变其地理范围，而无需遗传分化。