EVOLUTIONARY ACTIVITY IN THE SOUTHERN PART OF AFRICA: EVIDENCE FROM THE AMPHIBIA

Abstract

Hewitt's pioneering zoogeographical treatment of the southern African herpetofauna is considered in the light of subsequent taxonomic research on the Amphibia, also in the light of biogeographical theorising, where two opposing dispersalist models (peripheral plesiomorphy and peripheral apomorphy) and the vicariance model have made appearances. Hewitt's picture of a distinctive extra-tropical fauna has continued to be confirmed: ten of the thirty amphibian genera currently recognised in southern Africa seem to have arisen or proliferated south of the Limpopo Basin. This high level of evolutionary activity in the southern part of Africa leads to the question of why the southern region has been such a productive theatre of evolution, and whether there are indications of more than one major theatre of evolution. Data from the earth sciences are currently too sparse to provide decisive help in reconstructing the histories of the southern genera; there is a need for herpetologists to carry out phylogenetic investigations into sister groups of these genera.