|
Laboratoire de paléontologie des Vertébrés, Université Paris VI, 4 place Jussieu, 75252 Paris cedex 05, France
During the Triassic, free dispersal of terrestrial vertebrates was possible in Pangaea; however provinciality appeared in Gondwana. Distribution of Triassic vertebrates may be explained even if the Earth diameter did not expand and if Pacifica did not exist. During the Jurassic, a free land communication persisted between Gondwana and Laurasia, and provinciality is not demonstrated. A Gondwanan pattern emerged during the Cretaceous, but since that time it is not possible to identify a global difference between Gondwanan faunas and Laurasian ones. An African/South American terrestrial community developed until the Aptian. Subsequently, the opening of South Atlantic hindered interchanges between these two areas, but did not end them; exchanges might have taken place then via trans-Atlantic filter, or sweepstakes, routes. For the Cretaceous/Eocene time interval, crossings of the Tethys occurred intermittently, the major event being the interchange that took place between North and South America by latest Cretaceous. By the Cretaceous/Palaeocene transition, a terrestrial route probably linked the still southern Indian Plate to Laurasia. It is uncertain whether this route reached Madagascar. After the Eocene/Oligocene transition, exchanges between Gondwanan continents vanished, whereas exchanges between Gondwanan areas and Laurasia sometimes occurred.
