|© O'Reilly, X. (2010)|
Madagascar lies off the heal of the African continent. The world’s fourth largest island, on the map it is dwarfed by Africa’s shadow – but only in size. Famous for the immense variety of weird and wonderful organisms it is home to, most of which are found nowhere else, Madagascar’s unique biological catalogue is the result of millions of years of evolution in isolation, as well as its dramatically varied relief. Its most famous inhabitants, by far, are the lemurs – a whole group of endemic primates that come in a variety of forms, each uniquely adapted to specific niches throughout island’s amazing range of habitats.
But lemurs are thought to have arrived on the island after its split from Africa – what was living on Madagascar at the time of its birth? What proportion of its current terrestrial vertebrate fauna actually split away with the island and what proportion was to invade it after isolation? Certainly Madagascar received terrestrial migrants despite its geographical isolation – but how did they get there?
Madagascar was ripped from Africa’s side some 165 million years ago (Rabinowitz et al., 1983), together with what 88 million years ago split off to charge into the Asian mainland and become India (Storey et al., 1995).
For millions of years Madagascar has been cut off from any other land mass, giving natural selection full reign to explore and exploit the island’s staggering variety of habitats born from it’s massive geological diversity. Today it is home to an incredibly diverse array of organisms, most of which are endemic, such as the aforementioned lemurs.