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）的康提基号（Kon-Tiki）从南美洲出发地航行102天、跨越4000公里后，于土阿莫土群岛（Tuamotu archipelago）登陆，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佐证。鬣蜥科蜥蜴（Iguanid lizards）与蚺亚科蛇类（boine snakes）是冈瓦纳古陆（Gondwana）的古老演化支，其分布格局已被证实受大陆漂移作用影响。然而它们在太平洋岛屿上的神秘出现，却催生了“从美洲跨8000公里以上漂流扩散”这类异想天开的推论。我们结合最新分子数据与分化时间估算结果，重新审视这一扩散假说。研究结果表明，该类群的分化发生在古近纪早期（距今5000万至6000万年），且其起源更可能来自亚洲或澳洲（通过陆桥实现陆生迁移）。由于亚化石记录显示，鬣蜥（而非蛇类）曾是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不见这些物种的身影，也就不足为奇。综合以上发现，可证明人类活动对这些类群造成了显著影响，这一案例也可作为人类活动模糊生物地理学历史的典型例证。我们认为，这类陆生连接通道才是促成太平洋岛屿物种殖民的关键因素。