The dawn of the "Age of Mammals" in South America: Geography and evolution during the Late Cretaceous Paleocene span

ORTIZ JAUREGUIZAR, EDGARDO; PRADO, JOSÉ LUIS; PASCUAL, ROSENDO

Lyon

Mesa redonda; Table Ronde Européene "Paléontologie et Stratigraphie d'Amérique Latine"; 1992

Université Claude Bernard, Lyon

In this communication, we analyzed rhe dawn of the "Age of Mammals" in South America. Throughout the late Cretaceous-Paleocene span there has been recognized three different stages that decisively marked the dawn of the "Age of Mammals" in South America. We have named them Faunistic Cycles: Somuncurian (Campanian-?Maatrichtian), Cochabambian (late Early Paleocene), and Eopatagonian (middle to Late Paleocene). We analyzed the pattern of change of the land-mammal communities from a taxonomic (diversity of genera) and ecologic (trophic types) point of view.  To us, the particular pattern of evolution of the South American land-mammal faunas  is  tightly connected to the geological and geographical changes that occurred along the Late Cretaceous-Early Paleocene span.