Rabbs' fringe-limbed treefrog
This charismatic little frog may have been the loneliest creature on Earth: Until September 2016, only one specimen was known to exist in the world, at the Atlanta Botanical Garden in Georgia. But Toughie, as the staff called him, has died; he was about 12 years old.
This is the latest species to fall victim to the devastating chytrid fungus, an infectious disease of amphibians believed to be the principle reason for the sharp decline in amphibian biodiversity around the world.
The Atlanta specimen previously had a companion — a male at Zoo Atlanta — until it had to be euthanized in 2012 after its health began to fail. The last known recording of the species in the wild was in 2007. The region where it was heard later became infested with the chytrid fungus, and the frog's characteristic croaks haven't been heard since.