Data from: Influences of past climatic changes on historical population structure and demography of a cosmopolitan marine predator, the common dolphin (genus Delphinus)

Climatic oscillations during the Pleistocene have greatly influenced the distribution and connectivity of many organisms, leading to extinctions but also generating biodiversity. While the effects of such changes have been extensively studied in the terrestrial environment, studies focusing on the marine realm are still scarce. Here we used sequence data from one mitochondrial and five nuclear loci to assess the potential influence of Pleistocene climatic changes on the phylogeography and demographic history of a cosmopolitan marine predator, the common dolphin (genus Delphinus). Population samples representing the three major morphotypes of Delphinus were obtained from ten oceanic regions. Our results suggest that short-beaked common dolphins are likely to have originated in the eastern Indo-Pacific Ocean during the Pleistocene and expanded into the Atlantic Ocean through the Indian Ocean. On the other hand, long-beaked common dolphins appear to have evolved more recently and independently in several oceans. Our results also suggest that short-beaked common dolphins had recurrent demographic expansions concomitant with changes in sea surface temperature during the Pleistocene and its associated increases in resource availability, which differed between the North Atlantic and Pacific Ocean basins. By proposing how past environmental changes had an effect on the demography and speciation of a widely distributed marine mammal, we highlight the impacts that climate change may have on the distribution and abundance of marine predators and its ecological consequences for marine ecosystems.

更新世（Pleistocene）期间的气候波动极大地影响了众多生物的分布与种群连通性，既引发了物种灭绝，也推动了生物多样性的形成。尽管此类环境变化的影响在陆地生态系统中已得到广泛研究，但针对海洋领域的相关探索仍较为匮乏。本研究依托1个线粒体基因座与5个核基因座的序列数据，评估了更新世气候变迁对广布性海洋捕食者——普通海豚（海豚属Delphinus）的系统地理学与种群历史的潜在影响。研究团队从10个大洋区域采集了代表海豚属3种主要形态型的种群样本。结果显示，短喙普通海豚大概率于更新世时期起源于印度-太平洋东部海域，并经由印度洋扩张至大西洋海域。相较而言，长喙普通海豚似乎在多个大洋中独立演化而来，且出现时间相对较晚。本研究还发现，短喙普通海豚曾发生多次种群扩张事件，这与更新世期间海表温度变化及其伴随的资源可获得性提升相契合，且北大西洋与太平洋海盆的此类扩张模式存在显著差异。本研究阐明了过去的环境变化对广泛分布的海洋哺乳动物的种群动态与物种形成的影响机制，借此凸显了当前气候变化对海洋捕食者分布与种群数量的潜在影响，以及其对海洋生态系统造成的生态后果。