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Posts Tagged ‘amphibians’

Lost Rainbow Toad Found After 87 Years

14 Jul

By Mark Brown, Wired UK

Herpetologists at Conservation International have rediscovered the exotic Sambas stream toad (aka Borneo rainbow toad, aka Ansonia latidisca) after 87 years of evasion, and released the first ever photographs of the brightly colored amphibian.

The spindly-legged species was last seen in 1924 and European explorers in Borneo only made monochrome illustrations of it. A decade or so later, the CI and the SSC Amphibian Specialist Group added the species to its World’s Top 10 Most Wanted Lost Frogs campaign.

Indraneil Das of Universiti Malaysia Sarawak decided to hunt down the lost frog, and his team looked in the nearby area of Western Sarawak. In the summer of 2010 they made evening searches along the 1,329 meter high ridges of the Gunung Penrissen range to look for the toad.

After months of fruitless hunting, Das decided to include higher elevations in the team’s search. Then, one night, graduate student Pui Yong Min found the small toad two meters up a tree. Later they found another.

In the end the team had found three individuals of the missing toad species — an adult female, an adult male and a juvenile, ranging in size from 51 mm to 30 mm. All three toads exhibited those gangly limbs and the brightly colored patterns on their backs.

Talking about his team’s discovery in a press release, Das says, “They remind us that nature still holds precious secrets that we are still uncovering, which is why targeted protection and conservation is so important.”

Robin Moore of Conservation International agrees, saying in the release, “it is good to know that nature can surprise us when we are close to giving up hope, especially amidst our planet’s escalating extinction crisis.”

The slender-legged critter is only the second species on the “World’s Top 10 Most Wanted Lost Frogs” list to be found. In September 2010, the Rio Pescado Stubfoot Toad was rediscovered in Ecuador after 15 years of hiding. The spotty frog is sadly clinging on to survival.

The other frogs include the Costa Rican golden toad, the Australian gastric brooding frog, the Mesopotamia beaked toad from Colombia, Jackson’s climbing salamander, the African painted frog, the Venezuelan scarlet frog, the hula painted frog and the Turkestanian salamander — this hide and seek champion hasn’t been seen since 1909.

Image: Indraneil Das/Conservation International

Source: Wired.co.uk

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Creepy ‘Human Fish’ Can Live 100 Years

21 Jul

The olm, a foot-long salamander nicknamed “the human fish” because of its fleshy skin and tubular shape, is certainly a strange-looking animal. But beneath the surface, they’re even weirder: Olms can live for 100 years, far longer than any other amphibian.

Scientists have no idea why.

“This species raises questions regarding aging processes,” write researchers led by biologist Yann Voituron of France’s Université Claude Bernard in a July 21 Biology Letters study.

The olms studied by Voituron’s team are part of a population established 48 years ago to help conserve the rare amphibian, which is found in caves in Croatia and Slovenia.

When the project began, the olms were about 10 years old, making them nearly 60 now. Yet they “do not show any time of senescence,” write the researchers, who estimate the olm’s average lifespan to be 69 years, with an upper limit at the century mark.

Living in a stable environment without predators has made it possible for olms to have long lives, but the mechanisms underlying their longevity are unknown. In general, long life correlates with a large body size, but the half-pound salamanders are pipsqueaks compared to the next-longest-lived amphibian, the 50-pound Japanese salamander, which clocks in with a 55-year lifespan.

Voituron’s team thought olms might have extremely slow metabolisms, but they proved metabolically similar to other amphibians, including African bullfrogs and European toads that live for about 40 years.

The researchers also wondered if olms might have special tricks for cleaning up oxygen-free radicals, the DNA-damaging molecules produced when cellular mitochondria turn nutrients into energy. Free-radical accumulation is linked to aging, but the olm’s antioxidant activity is nothing special.

“The olm presents a paradox,” wrote the researchers. “Neither its basal metabolic rate nor its antioxidant activity, the two most cited mechanisms that should be involved in enhancing lifespan, differ from species with a more reduced lifespan.”

Voituron is now testing whether the olm might have extra-efficient mitochondria that emit fewer free radicals to begin with. “If you manage to produce more energy with less free-radical production, then you can avoid aging and increase lifespan,” he said.

Image: Olivier Guillaume.

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Citation: “Extreme lifespan of the human fish (Proteus anguinus): a challenge for ageing mechanisms.” By Yann Voituron, Michelle de Fraipont, Julien Issartel, Olivier Guillaume Jean Clobert. Biology Letters, online publication, July 21, 2010.

Brandon Keim’s Twitter stream and reportorial outtakes; Wired Science on Twitter. Brandon is currently working on a book about ecological tipping points.

 
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