Competing paradigms of Amazonian diversification and the Pleistocene refugium hypothesis

Evidence from butterflies and birds suggests that most extant Amazonian species arose during the Pleistocene (< 2.6 Ma). If these speciation events share common, extrinsic causes, their explanation probably involves climate‐driven biogeographical shifts, because the major orogenic events shaping the biogeography of the Neotropics were over by then. In the light of these observations, criticisms of the Pleistocene refugium hypothesis are...