A search for frogs believed to be extinct has instead led scientists to discover some new ones.

科学家们在搜寻可能已经灭绝的青蛙的时候意外发现一些新品种。

larvae¹: this tiny toad² apparently³ needs no tadpole⁴ stage" src="http://www.enread.com/upimg/allimg/101117/4_101117061249_1.jpg" width="304" height="304" />
Life without larvae: this tiny toad apparently needs no tadpole stage

Three species hitherto（迄今） unknown to science have been found in Colombia.

They include a poison-secreting rocket frog and two toads⁵（蟾蜍） . All three are tiny and tend to be most active in daytime, which is unusual for amphibians⁷（两栖动物） .

However, the same expedition to Colombia failed to find the species it was hoping to rediscover, the Mesopotamia beaked⁸（有喙的，鸟嘴状的） toad.

The disappointment provoked by that non-discovery turned to glee（快乐，欢欣） when the conservation scientists came across the three new species.

The 3-4cm red-eyed toad, discovered at an altitude of 2,000m, evoked⁹ particular fascination¹⁰.

"I have never seen a toad with such vibrant¹¹ red eyes," said Robin¹² Moore from Conservation International, the scientist who set up the rediscovery project.

"This trait is highly unusual for amphibians, and its discovery offers us a terrific opportunity to learn more about how and why it adapted this way."

The other new toad is also tiny - less than 2cm long - with a beak-shaped head that Dr Moore compared to the snout（鼻子，猪嘴） of Montgomery Burns, the villain¹³ of The Simpsons TV series.

George Meyer, a long-time Simpsons writer and amphibian⁶ enthusiast¹⁴, commented: "The toad's imperious（专横的，迫切的） profile and squinty¹⁵（斜视的） eyes indeed look like Monty Burns."

The reason why it has not been identified previously¹⁶ is probably because the species skips the tadpole（蝌蚪） stage, instead producing toadlets that resemble the fallen leaves of the forest floor in which they live.

The third newcomer is a rocket frog, a member of the poison dart¹⁷ family - though not as poisonous as many of its cousins.

The amphibian search, co-ordinated by Conservation International along with the International Union for the Conservation of Nature, began in August and is the first co-ordinated attempt to look for species believed to be extinct.

Expeditions have been mounted in 19 countries in search of 100 lost species.

So far, three have been found: a Mexican salamander not seen since its discovery in 1941, a frog from the Ivory Coast last observed in 1967, and another frog from Democratic Republic of Congo not seen since 1979.

Despite the discoveries and rediscoveries, the team emphasises that overall, the global outlook for amphibians is still bleak¹⁸.

The remainder of species targeted by the current search have remained undetected, suggesting that they are indeed extinct.

And the latest Red List of Threatened Species, released during the UN biodiversity summit last month, put 41% of amphibians on the danger list, with most of the threats continuing to intensify¹⁹.