The newspaper compares the rediscovery to "the Dead Sea Scrolls of nature conservation."
The rare frog, which is unique to Israel's Hula valley, was spotted in the Hula Nature Reserve by park warden Yoram Malka.
He described the moment to Haaretz:
"I saw something jump that didn't look familiar. I rushed over and caught a frog, and when I turned it over I saw that it had a black belly with white spots, the identifying mark of the painted frog. I immediately returned [with it] to the reserve's office and took out the animal handbook."
His discovery was then verified by amphibian specialists. Scientists say the frog, a female, will be returned to the wild as soon as possible.
More from GlobalPost: PHOTOS: Endangered animals on the IUCN Red List
Only five known specimens of the frog have ever been collected, said the Jerusalem Post, all in the 1940s and 50s.
The species was believed to have died out when Lake Hula and the surrounding marshes were drained in the 1950s. The frog was officially declared extinct in 1996.
Its reappearance may be linked to recent improvements in water quality at the Hula reserve, said Haaretz.
Researchers will now attempt to find out whether there are other painted frogs in the reserve.
Last time specimens were captured, one frog ate the other, according to the Associated Press, which may indicate that the species is cannibalistic.
More from GlobalPost: End of Africa's black rhino