Was the Cape a biotic reservoir in the repopulation of Africa after the KT extinction event 66 MY ago?

The extinction of dinosaurs after a 10 km wide meteor struck Earth in today’s Caribbean, 66 million years ago, marked the division between the Cretaceous and Cenozoic (popularly known as the Age of Mammals). South Africa was one of four separate southern and eastern landmasses where some plants and primitive mammals survived. My proposed project would explore how those survivors have contributed to current biodiversity in Africa. Sub-Saharan African biogeography can be represented as two “land-locked archipelagos”, the Boreal (or Centre-West) realm and the Austral (or South-East) realm. Taxa with intra-continental origins can be supposed to have had an adaptive head start over later arrivals, especially within the Austral realm. Facets of such histories can be inferred from dated molecular clocks and by reference to the fossil record – both major sources for this study. Immigrants to “Island Africa” (which was ocean-bound on all sides for 10 million years) could only come in across “bridges”, all of which were in the north. I seek to reconstruct the relative roles, advantages and consequences of these two sources of evolutionary innovation – mainly among mammals but with some references to other taxa; and to highlight the complex, interesting and diagnostic histories of contemporary living species.