Lemurs' wet and wild past
Model shows how mammals could have 'rafted' to Madagascar.Geoff Brumfiel
The model, published today in Nature1, settles a long-running debate on how Madagascar's biodiversity came about. It may also provide clues about how prehistoric animals spread to other parts of the globe.
Lemurs rafted to Madagascar millions of years ago, a new model suggests.
ChGR/ iStockphoto.com
Madagascar is considered to be one of the world's most diverse — and imperiled — natural habitats. Its forests are home to more than 150 species of mammal alone — including ring-tailed lemurs, otter-like web-footed tenrecs, and giant jumping rats. But all of these mammals belong to just four orders.
Just why there are so many species and so few orders has been a mystery. Some researchers have proposed that there may have been a land bridge between Madagascar and the African mainland around 20-60 million years ago. But the geology of the region shows little evidence of such a link. Moreover, a land bridge would have allowed more orders of animal to reach the island.
An alternative hypothesis is that animals 'rafted' to the island. First mooted some 70 years ago by the American palaeontologist George Gaylord Simpson, the idea is that small mammals were inadvertently washed out to sea by storms and floated to Madagascar's shores. The survivors evolved over millions of years to fill numerous niches in the island's ecosystem.
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Read more here/Leia mais aqui: Nature
