On a global scale, the amphibian population has been waning. But according to a report published today in the journal Science, researchers have discovered more than 100 new species of frogs in the rain forest of Sri Lanka. The scientists say the find classifies the island as "an amphibian hot spot of global importance."

An international team led by Madhava Meegaskumbura of Boston University and Sri Lanka's Wildlife Heritage Trust categorized all the amphibians they could find in a 750-square-kilometer patch of remaining rain forest. By comparing the specimens to Sri Lankan samples stored in museums around the world and analyzing differences in appearance, genetics and behavior (including the animals' telltale croaks), the scientists identified 120 new species. The majority of these lay eggs that undergo what is known as terrestrial direct development. In this process, the eggs incubate on land before the frogs hatch as miniature adults, skipping the tadpole stage completely. Such growth could help explain why these animals have persisted, the scientists suggest, because many of the factors thought to be responsible for the decline of frog populations are particularly dangerous to water-based young. Finding such a plethora of frogs--despite the fact that Sri Lanka has already lost 95 percent of its original rain forest habitat--puts the island's amphibian diversity on par with that of tropical islands nearly 10 times its size, such as Borneo and Madagascar. The authors conclude that "other rich vertebrate faunas may await discovery elsewhere in tropical Asia."