Greater Gondwana and the Kawas sea coastal tetrapod fauna (Campanian-Maastrichtian)

SEBASTIÁN APESTEGUÍA

Sao Pedro, Brasil

Simposio; 6º Simpósio sobre o Cretáceo do Brasil / 2º Simposio sobre el Cretácico de América del Sur.; 2002

Universidad de Santa Clara

American Cretaceous paleogeography was related to Laurasia and Gondwana behavior and the opening of the South Atlantic. However, the existence of Greater Gondwana, would have allow between 110-70 m.y. ago, a coastal continuity among South America – Antarctic peninsula – continental Antarctica -Kerguelen-India-Madagascar. Extant coastal marine faunas are homogeneous. For it, Late Campanian coastal points should be studied comparatively in South Gondwanan regions. After Hay et al. consideration of the closing of aulacogens, Patagonian paleogeography was slightly modified. This region would have been close as a fan toward the east, narrowing the south Atlantic Ocean and reducing the climatic latitudinal zonation between the 40º and 50º S. The interamerican Late Campanian connection determined the existence of two sucessive faunistic associations: The first, continental and autochthonous, is characterized by fresh water dipnoan fishes, snakes, sphenodontids, saltasaurines, abelisaurids, monotremes, dryolestoids, docodonts and gondwanatheres. The second, mainly coastal and signed by allochtonous influences, implies the hadrosaur arrival, more squamates and therian mammals. The arrival “timing” of laurasic lineages, in a careful stratigraphic context, it will allow a better understanding of the faunistic sucessions along the coast of the Kawas Sea at the end of the Upper Cretaceous.