It's not often we can pinpoint the exact moment a species goes extinct, but today is that day: the world's last known Rabbs' fringe-limbed tree frog, a male known as "Toughie", has died. 

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The very last of his kind. Image: Atlanta Botanical Garden/Facebook

The tiny animal (Ecnomiohyla rabborum) was collected during a frog rescue mission in Panama back in 2005, a time when the deadly chytrid fungus was decimating amphibian populations in the region. Scientists had hoped to find a mate for the lonesome frog, but despite nine years of searching, Toughie remained the last known specimen until the bitter end.

"Knowing this day would come didn't make it any easier," says Mark Mandica, who cared for Toughie for seven years at the Atlanta Botanical Garden. "In that time, his sad story of being the very last of his kind had, in a powerfully sad way, made him an 'ambassador' for amphibian conservation and awareness. Amphibians are disappearing and their declines are telling us something we need to pay attention to."

Perhaps nothing underscores the poignancy of the loss quite like this 2014 recording of Toughie's call for a mate that quite likely did not exist:

The story of the Rabbs' fringe-limbed tree frog is not unique. Nearly 40 percent of the world's amphibians are currently in decline or already extinct. "There are other species out there, blinking out before we even have a chance to recognise what was happening, let alone reverse it," says Mandica. "It’s going to take all of us to make a difference for the amphibians, and ultimately, for us too."

During the last years of his life, Toughie was featured in countless magazines, as well as Joel Sartore's Photo Ark and the film Racing Extinction. Sartore's image of the frog was even projected on St Peter's Basilica in the Vatican last year as part of an awareness-raising public art project, while a recording of Toughie's vocalisation played for those gathered and millions of others around the world.

Of course, there is the chance that another Rabbs' fringe-limbed frog could be found in the future. These animals are known to inhabit the high canopy, and as John Platt reports for Scientific American, their lofty real estate of choice may have protected some stragglers from the chytrid.

We've actually seen such a "resurrection" before, with the Azuay stubfoot toad, a species thought to be extinct for more than a decade, and later rediscovered in the highlands of EcuadorBut based on what we know right now, Toughie's kind is gone for good.

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Top header image: Mark Mandica