Researchers have discovered evidence that iguanas from North America made an epic transoceanic voyage millions of years ago, landing in the South Pacific. These seafaring lizards traveled one-fifth of the way around the world, setting a record for the longest known transoceanic emigration among land vertebrates. The study highlights the incredible long-distance dispersal capability of iguanas and sheds light on their evolutionary history.
The genetic analysis of over 200 species of iguanas and related lizards revealed that Fijian iguanas are closely related to desert iguanas from Mexico and the American Southwest. This finding, together with the geography of fossil discoveries, supports the theory that ancestral iguanas rafted across the Pacific from North America to Fiji between 31 million and 34 million years ago. This massive oceanic journey likely led to the evolutionary split between Brachylophus and Dipsosaurus, showcasing the remarkable resilience of these reptiles.
The study suggests that iguanas may have rafted on vegetation rafts, a theory supported by their unique ability to survive in harsh conditions. The ancestral iguanas may have feasted on their raft during the voyage or entered a state of torpor to conserve energy. Additionally, their resistance to heat and dehydration, as well as their propensity to colonize new islands via rafting, make them well-suited for long trips at sea. These findings provide insight into the adaptability and survival strategies of iguanas in extreme environments.
The researchers’ analysis challenges previous hypotheses about the origins of Fijian iguanas and offers a new perspective on the evolutionary history of these reptiles. By combining genetic evidence with fossil data and geographical factors, the study paints a detailed picture of how iguanas undertook an extraordinary journey across the Pacific millions of years ago. The discovery underscores the role of chance events in shaping evolutionary trajectories over vast time scales.
The study’s findings have broader implications for understanding the dispersal and adaptation of species in response to changing environments. By exploring the genetic relationships and migration patterns of iguanas, researchers can uncover new insights into the evolutionary processes that have shaped biodiversity. The study exemplifies the power of interdisciplinary research in unraveling the mysteries of ancient migrations and ecological dynamics, paving the way for future studies on the resilience and survival strategies of diverse organisms.
