Vicariant biogeographic relationships have been commonly sought, inferred, or assumed between Africa and South America. Yet for disjunct distributions involving North America and the Old World, Africa is rarely considered. We present a molecular biogeographic study in the legume family that suggests a vicariant biogeographical relationship between Africa and North America. Such a relationship is likely to be shown with additional phylogenetic analysis to be prevalent among legume groups and other taxa that diversified during the Tertiary in seasonally dry tropical vegetation. If so, this finding would strengthen the hypothesis that the Tertiary North Atlantic land bridge had a significant influence on the Cenozoic formation of continental biotas, including that of Africa.

Communicating Editor: Jeff H. Rettig