Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Mol Phylogenet Evol. 2018 Oct;127:545-555. doi: 10.1016/j.ympev.2018.05.014. Epub 2018 May 17.
Sea-level change has been viewed as a primary driver in the formation of biodiversity. Early studies confirmed that Plio-Pleistocene sea-level changes led to the isolation and subsequent genetic differentiation of Southeast (SE) Asian organisms over short geological timescales. However, long-time consequences of sea-level fluctuations remain unclear. Herein, we analyze the evolutionary history of Althepus (spiders) whose distribution encompasses Indo-Burma and the Sunda shelf islands to understand how sea-level changes over shallow and deep timescales effected their history. Our integrative analyses, including phylogeny, divergence times, ancestral area reconstruction and diversification dynamics, reveal an intricate pattern of diversification, probably triggered by sea-level fluctuations during the Paleocene-Eocene and Plio-Pleistocene. The timing of one early divergence between the Indo-Burmese and Sundaic species coincides with late Paleocene and early Eocene high global sea levels, which induced the formation of inland seaways in the Thai-Malay Peninsula. Subsequent lowered sea levels could have provided a land bridge for its dispersal colonization across the Isthmus of Kra. Analyses suggest that Plio-Pleistocene sea-level rises contributed to recent divergence of many species. Thus, our findings cannot reject the hypothesis that sea-level changes during the Paleocene-Eocene and Plio-Pleistocene played a major role in generating biodiversity in SE Asia; sea-level changes can act as "species pumps".
海平面变化被视为生物多样性形成的主要驱动因素。早期的研究证实，上新世-更新世海平面变化导致东南亚生物在短地质时间内发生隔离和随后的遗传分化。然而，海平面波动的长期后果仍不清楚。在此，我们分析了分布于印度-缅甸和巽他陆架岛屿的 Althepus（蜘蛛）的进化历史，以了解浅时和深时海平面变化如何影响它们的历史。我们的综合分析包括系统发育、分歧时间、祖先区重建和多样化动态，揭示了多样化的复杂模式，可能是由古新世-始新世和上新世-更新世海平面波动触发的。印度-缅甸和巽他物种之间的一次早期分化的时间与晚古新世和早始新世的高全球海平面相吻合，这导致了泰国-马来半岛内陆海峡的形成。随后的海平面下降可能为其通过克拉地峡的扩散和殖民化提供了一个陆桥。分析表明，上新世-更新世海平面上升导致了许多物种的近期分化。因此，我们的发现不能否定上新世-更新世和古新世-始新世海平面变化在东南亚生物多样性形成中起主要作用的假说；海平面变化可以作为“物种泵”。
