Data from: Tracing the origins of Iguanid lizards and Boine snakes of the Pacific

In 1947, when Thor Heyerdahl’s Kon‐Tiki hit ground in the Tuamotu archipelago, 102 days and 4,000 km from its point of origin in South America, he inadvertently provided support for one of the most remarkable hypotheses of vertebrate dispersal. Iguanid lizards and boine snakes are ancient Gondwanan lineages whose distribution has been demonstrated to have been influenced by continental drift. Their enigmatic presence on the islands of the Pacific, however, has drawn fantastical conclusions of more than 8,000‐km rafting from the Americas. We reexamine the hypothesis of dispersal in light of new molecular data and divergence time estimates. Our results suggest an early Paleogene (50–60 million years) divergence of these groups and the plausibility of an Asiatic or Australian (over land) source. Because the subfossil record indicates that iguanas (but not snakes) were a primary food source of island inhabitants, the absence of these species from islands with a longer history of human presence is unsurprising. Together these findings are taken as evidence of the influence humans have had on these taxa and are put forth as an example of anthropogenic obfuscation of biogeographic history. We suggest that this history is one of terrestrial connections permitting the colonization of the islands of the Pacific.1947年，托尔·海尔达尔（Thor Heyerdahl）率领的康提基号（Kon-Tiki）在土阿莫土群岛（Tuamotu archipelago）靠岸，该航程从南美出发地耗时102天、跨越4000公里，这一事件无意间为脊椎动物扩散领域最具影响力的假说之一提供了实证支撑。鬣蜥科（Iguanid）蜥蜴与蚺亚科（boine）蛇类均为冈瓦纳古陆（Gondwanan）的古老演化支系，已有研究证实其分布格局受大陆漂移过程的深刻影响。然而它们在太平洋岛屿上的神秘分布，却催生了“从美洲跨8000公里以上远洋漂浮扩散”这类充满臆测的推论。本研究结合最新分子数据与分化时间估算结果，重新审视该扩散假说。研究结果显示，这两类群的分化发生在古近纪早期（距今5000万至6000万年），其起源更可能来自亚洲或澳大利亚（经由陆地路径扩散）。此外，亚化石（subfossil）记录表明，鬣蜥（而非蛇类）曾是太平洋岛屿原住民的主要食物来源，因此在人类定居历史更为悠久的岛屿上未发现此类物种，便不足为奇。综合上述发现，可证明人类活动对这些类群产生了显著影响，本研究亦可作为“人类活动模糊生物地理学（biogeographic）历史”的典型案例。我们认为，太平洋岛屿的殖民过程实则依托古陆地连接完成。