Biological evidence supports an early and complex emergence of the Isthmus of Panama

摘要: The linking of North and South America by the Isthmus Panama had major impacts on global climate, oceanic atmospheric currents, biodiversity, yet timing this critical event remains contentious. is traditionally understood to have fully closed ca. 3.5 million years ago (Ma), date has been used as a benchmark for oceanographic, climatic, evolutionary research, but recent evidence suggests more complex geological formation. Here, we analyze both molecular fossil data evaluate tempo biotic exchange across Americas in light evidence. We demonstrate significant waves dispersal terrestrial organisms at approximately 20 6 Ma corresponding events separating marine Atlantic Pacific oceans 23 7 Ma. direction their rates were symmetrical until last Ma, when northern migration American lineages increased significantly. Variability among taxa or vicariance not explained ecological factors tested these analyses, including biome type, ability, elevation preference. Migration was therefore generally regulated intrinsic traits likely reflects presence emergent terrain several millions earlier than commonly assumed. These results indicate that dramatic turnover associated with Great Biotic Interchange long process began early Oligocene–Miocene transition.