Israeli park ranger Yoram Malka caught only a fleeting glimpse of the frog as it leapt across the road, but he knew it was something special.
When he first saw the frog in northern Israel's Hula Valley, Malka jerked his utility vehicle to a stop, bounded out of his seat, and jumped atop it, catching the creature in his hands.
The animal had a mottled backside and a black belly with white dots. It belonged to a species that most scientists thought had disappeared from the Earth more than half a century ago.
In fact, the Hula painted frog was the first amphibian to officially be declared extinct, in 1996. Prior to Malka's 2011 encounter, the animal had not been spotted alive in nearly 60 years.
When Sarig Gafny, a river ecologist at Israel's Ruppin Academic Center, received Malka's cell phone picture of the frog, he recalled that "everything fell out of my hands."
"I forgot about my fever, jumped into my car, and drove two hours north to see it," said Gafny, the coauthor of a study published Tuesday in the journal Nature Communications detailing the frog's rediscovery.
The last confirmed sighting of the frog was in 1955, after the draining of the Hula Valley wetlands, only about a decade after the amphibian had been discovered. Survey trips dedicated to searching for the frog were launched as recently as 2004, but to no avail.
Since 2011, however, Gafny and his team have discovered several more specimens, bringing the tally of known Hula painted frogs up to 14.
Gafny says that there may be between 100 to 200 Hula painted frogs living in the Hula Valley. While not bad for a species once thought extinct, scientists think the frog's range and population levels are greatly reduced from what they once were.
Based on detailed studies of DNA and skeletal morphology from recent specimens of the Hula painted frog, study author and Hebrew University of Jerusalem paleontologist Rebecca Biton has concluded that the species is the last living member of Latonia, a genus of frogs once found across Europe, as far west as Spain.
It had initially been catalogued within another frog genus, Discoglossus, when it was first discovered in the 1940s.
Fossils of Latonia frogs as old as two million years have also been found in Israel, but the group was thought to have died out more than 10,000 years ago.
A 'Living Fossil'
Now, the Hula painted frog is considered a rare example of a so-called living fossil, an organism that has retained the same form over millions of years and that has few or no living relatives.
Only about a dozen other "living fossils" are known, the most famous of which may be the coelacanth, an ancient fish that can trace its ancestry back to the days of the dinosaurs.
Robin Moore, the creative director of Amphibian Survival Alliance, called the Hula painted frog's rediscovery "incredible."
"It's a real testament to the resilience of nature if given the chance," said Moore, who leads a project called Search for Lost Frogs.
"Scientists tend to err on the side of caution before declaring something extinct, so we were pretty sure this frog was gone," he said.
Still in Danger
Moore said that despite the Hula painted frog's rediscovery, amphibians are still in peril worldwide, as they confront habitat destruction, pollution, disease, and climate change.
At the same time, he said that such success stories offer much needed hope.
"It's a dangerous message to send that we're too late to do anything to save these species," he said. "Because then people won't do anything."
Gafny said that his team is seeking funding to continue its studies of the Hula painted frog, which he called a "tabula rasa."
"We know nothing about its life history," he said. "We don't know if it's active at night. We don't know when it breeds, or how it breeds, or what its tadpoles look like."