Brief History of South American Biogeography

The early history of the study of vertebrate palaeobiogeography in South America is marked in the first decade of the twentieth century by two opposite and competing hypotheses, authored by Florentino Ameghino (1906) and Albert Gaudry (1906, 1909), respectively. Ameghino, proposed that South America, specifically Patagonia, was the cradle and source of most (or all) extant mammals, including man. Otherwise, Gaudry concluded that most anatomical similarities shared by South American mammals and those from other continents may be regarded as mere convergences and had nothing to do with the origin of other groups elsewhere. Authors following the later scheme sustain that South America do not played any role in the early history of modern mammals (nor any mayor extant clade), and represents a dead-end for the evolution of the clade. In spite of diverse critics coming from different sources, the later still prevails as the conventional model for understanding the evolution of South American biota, particularly mammals.