Unlocking the Secrets of a Lost World

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Science  31 Aug 2012:
Vol. 337, Issue 6098, pp. 1020
DOI: 10.1126/science.337.6098.1020-a

The ancient sandstone table mountains, or tepuis, of the tropical South American Guayana Shield are legendary “lost worlds” renowned for their inaccessibility, mystery, and isolation. Rising hundreds of meters vertically from the surrounding savannas and forests, the summits of individual tepuis are known to harbor high percentages of endemic species of plants and animals that have evolved in isolation over millions of years. Or do they? Kok et al. helicoptered onto the summits of 17 tepuis to take tissue samples from amphibian species for genetic analysis. Phylogenetic analysis of mitochondrial gene fragments indicated surprisingly close affinities between many of the taxa on separate peaks, indicating that the barriers to gene flow may have been less complete than hitherto thought. The genetic data suggest that dispersal between summits may have been taking place through the Pleistocene and into the Holocene, so that substantial elements of the fauna may be less than 1 million years old—far less than the forbidding nature of the tepuis would seem to predict.

Curr. Biol. 22, R589 (2012).

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