ATLANTA -- The death of a rare tree frog marks the last documented member of a species relatively new to science, according to the Atlanta Botanical Garden.

The Rabbs’ fringe-limbed tree frog, estimated to be about 12 years old, was found deceased in its enclosure Monday by staff during their daily routine health inspection, said Brad Wilson, the Garden’s veterinarian and Amphibian Conservation Scientist. Because the frog was the last known living member of its species in captivity, a standing protocol was in place for the recovery of genetic material that could be used to further study the species. Because of that, an evaluation to determine an exact cause of death cannot be performed.

The frog, known as “Toughie,” was in the FrogPod for 12 years and rarely made a sound. However, on one occasion, scientists at the FrogPod were able to record his mating call.

“We are extremely saddened by the loss of this frog and its species, which highlights the importance of amphibian research and conservation work worldwide,” said Mary Pat Matheson, the Garden’s President & CEO. “If we lose our amphibians, we lose a significant component in efforts to preserve biodiversity globally.”

PHOTOS: Toughie, the last-ever frog of his type

Scientists estimate that one-third to one-half of amphibian species worldwide are threatened with extinction, many due to habitat loss and diseases such as chytridiomycosis, caused by an aquatic fungal pathogen.

More than a decade ago, the Garden, Zoo Atlanta and Southern Illinois University sent a team of scientists to Panama to collect live animals before the deadly chytrid disease struck the area. Among the frogs they brought back to Atlanta was a species of tree frogs (Ecnomiohyla rabborum) new to science, the Rabbs’ frog.

Identified in 2005 by Zoo Atlanta herpetology curator Joseph Mendelson, it was later named for conservationists George and Mary Rabb. In time, the disease did arrive in Panama, and many of the frogs disappeared.

The frog’s death serves as a stark reminder of the importance of the Garden’s conservation work in working with partner institutions to prevent species loss. This is done by surveying wild populations, monitoring restored populations, establishing safeguarding collections, and developing new propagation protocols for rare species.