Data from: The biogeography of Sulawesi revisited: is there evidence for a vicariant origin of taxa on Wallace’s “anomalous island”?

Sulawesi, the largest island in the Indonesian biodiversity hotspot region Wallacea, hosts a diverse endemic fauna whose origin has been debated for more than 150 years. We use a comparative approach based on dated phylogenies and geological constraints to test the role of vicariance versus dispersal in the origin of Sulawesi taxa. Most divergence time estimates for the split of Sulawesi lineages from their sister groups postdate relevant tectonic vicariant events, suggesting that the island was predominantly colonized by dispersal. Vicariance cannot be refuted for 20 % of the analyzed taxa, though. While vicariance across Wallace’s Line was only supported for one arthropod taxon, divergence time estimates were consistent with a “tectonic dispersal” vicariance hypothesis from the East in three (invertebrate and vertebrate) taxa. Speciation on Sulawesi did not occur before the Miocene, which is consistent with geological evidence for more extensive land on the island from that time. The Pliocene onset of periodic sea-level changes may have played a role in increasing the potential for dispersal to Sulawesi. A more extensive taxon sampling in Wallacea will be crucial for refining our understanding of the region’s biogeography and for testing hypotheses on the origin of taxa on its most important island.

苏拉威西岛是印度尼西亚生物多样性热点区域华莱士区（Wallacea）内最大的岛屿，孕育了多样的特有动物类群，其起源议题已争论逾150年。本研究采用基于定年系统发育树与地质约束的比较研究范式，检验隔离分化（vicariance）与扩散（dispersal）在苏拉威西岛类群起源中的作用。绝大多数苏拉威西支系与其姊妹群的分化时间估算结果均晚于相关构造隔离分化事件，表明该岛主要通过扩散作用实现物种拓殖。但仍有20%的被分析类群无法排除隔离分化的影响。尽管仅在1个节肢动物类群中得到了华莱士线（Wallace’s Line）两侧存在隔离分化的支持，但有3个涵盖无脊椎动物与脊椎动物的类群的分化时间估算结果，与源自东侧的“构造扩散型隔离分化”假说相符。苏拉威西岛的物种形成并未早于中新世，这与该时期岛上陆地范围更广的地质证据相吻合。上新世周期性海平面变化的启动，或许对提升苏拉威西岛的物种扩散拓殖潜力起到了作用。对华莱士区开展更广泛的类群采样，对于深化我们对该区域生物地理学的认知，以及检验这座核心岛屿上类群起源的相关假说，均具有至关重要的意义。