Fossil amphibians and reptiles and the Africa–South America connection

Abstract

Abstract Although it was the subject of much controversy among geologists and palaeontologists until well into the 1960s, the former existence of a land connection between Africa and South America no longer needs to be demonstrated. Within the general framework of plate tectonics and continental drift, it is now clear that Africa and South America were once part of the southern super-continent Gondwana, itself a constituent of Pangaea during the Late Palaeozoic and the Early Mesozoic. The distribution of some fossil amphibians and reptiles was one of the important palaeobiogeographical arguments in favour of such reconstructions. The occurrence of very closely related representatives of a group of small early reptiles, the mesosaurs, in the Permian of South America and South Africa, for instance, was used as evidence of a connection between Africa and South America in the Late Palaeozoic, well before continental drift became generally accepted. The Late Triassic dinosaur faunas of South Africa and South America also exhibit resemblances—which is not surprising in a palaeo-biogegraphical situation of global faunal similarity, due to the existence of Pangaea. Although it may seem paradoxical, the Africa-South America connection becomes an interesting scientific problem mainly when it ceases to exist, when the opening of the proto-Atlantic Ocean sometime in the Cretaceous separates the two continents from each other and makes faunal interchange increasingly difficult. A comparative history of amphibians and reptiles in South America and Africa, through the Cretaceous and into the Tertiary, reveals similarities and divergences suggesting a pattern of faunal exchanges in which vicariant evolution and dispersal across barriers both played a part.