The world’s last known Rabbs’ fringe-limbed tree frog (Ecnomiohyla rabborum) has died.

Known as “Toughie,” the tiny male frog, originally from Panama, spent the past few years living by himself at Atlanta Botanical Garden. The species has not been observed in the wild since 2007, just two years after it was first discovered by scientists.

Toughie’s death follows four and a half years after another Rabbs’ tree frog died at Zoo Atlanta. That frog was euthanized in 2012 after its health began to decline.

Both of these Rabbs’ tree frogs were collected in Panama while scientists were there investigating the deadly chytrid fungus, which has devastated amphibian populations in that country and around the world.

Although no signs of wild Rabbs’ tree frogs have shown up in the past nine years, at least one scientist still held out hope they might one day be found again. “The habits of this genus can make them extremely difficult to find if they remain high up in the trees,” says Jonathan Kolby, director of the Honduras Amphibian Rescue and Conservation Center. “Being that this species breeds in tree cavities up in the canopy, I would hope that this behavior offers some protection from exposure to chytrid fungus, although the species was reported to have become much less common after the arrival of chytrid in the region.”

Still, the likelihood remains that the Rabbs’ fringe-limbed tree frog is now truly gone. That’s notable, not just for the extinction, but for the circumstances around Toughie’s life. Extinctions, you see, are very rarely witnessed by humans. Instead, they tend to be discovered years or even decades after the last member of a species gave up the fight. The Rabbs’ tree frog was a rare exception. For the past four and a half years, Toughie has been a very public ambassador for his lost species, and for all of the frog species going extinct around the world during the current amphibian extinction crisis. How many thousands of people who walked by his enclosure at Atlanta Botanical Garden felt the pull and gravity of his inevitable extinction? As the organization posted today on Facebook, “He will be missed by Garden staff and visitors alike.”