In 1996, after four decades of failed searches, the Hula painted frog became the first amphibian to be declared extinct by an international body — a portent of the crisis that now threatens the entire class. But it seems that reports of the creature’s death had been greatly exaggerated.
In October 2011, a living individual was found in Israel’s Hula Nature Reserve, and a number of others have since been spotted. “I hope it will be a conservation success story,” says Sarig Gafny at the Ruppin Academic Center in Michmoret, Israel, who led a study of the rediscovered animal. “We don’t know anything about their natural history and we have to study them. The more we know, the more we can protect them.”
Gafny's team has not only rediscovered the frog, but also reclassified it. It turns out that the Hula painted frog is the last survivor of an otherwise extinct genus, whose other members are known only through fossils. The work appears today in Nature Communications1.
“It’s an inspiring example of the resilience of nature, if given a chance,” says Robin Moore, who works for the Amphibian Specialist Group of the the International Union for Conservation of Nature in Arlington, Virginia, and has accompanied Gafny on frog-finding trips. “We need flagships for conservation to generate a sense of optimism, and this story is about as good as it gets. The frog is even included in school curricula, and my taxi driver to Tel Aviv airport knew its story!”
While studying invertebrates in the reserve, Gafny met Yoram Malka, a ranger for the Israel Nature and Parks Authority, who had a gut feeling that the frog was still alive. “He said, 'give me a year, and I’ll get you a specimen',” recalls Gafny. The following year, a frog leapt in front of Malka while he was on a routine midday patrol. Later that day, Gafny returned to his office to find 20 missed calls on his phone. “He told me, 'Sarig, we found it!'.”
The team has since seen 14 individuals, 10 of them alive. Gafny has also been contacted by a tourist who snapped a photo of the frog in 2009, two years before the official rediscovery.
When the Hula painted frog was first described in 1943, it was classified as Discoglossus nigriventer, alongside other living species within the same genus. But when Gafny and his colleagues sequenced DNA from their specimens, they found that the frog sits outside the Discoglossus clade, which they estimate it diverged from around 32 million years ago.
The frogs’ skeletons supported the DNA evidence. Rebecca Biton at the Hebrew University of Jerusalem in Israel put dead specimens in a computed tomography scanner (see picture) and found that they had the distinguishing features of Latonia — a fossil genus whose youngest specimens were 15,000 years old.
Today, the surviving frogs — now renamed Latonia nigriventer — live in densely vegetated areas near a single pond in the nature reserve. Biologists usually need to crawl through blackberry bushes and dig through rotting leaf litter to find them. This may explain why earlier searches failed, but Gafny also hopes that the frogs are becoming easier to find because their numbers are rising.
The Hula Nature Reserve was set up in 1964 to protect a patch of wetland from severe degradation and encroaching agricultural development. Since then, “the quantity and quality of water has improved”, Gafny says. And with no trace of the deadly chytrid fungus that is killing amphibians worldwide, he hopes that conservation efforts can keep the Hula painted frog alive.
“Habitat loss remains the biggest threat to the survival of amphibians around the world, and it’s important to be reminded that strategies to address it can work,” says Moore. “We need these positive stories amid the doom and gloom.”
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