The Bururi long-fingered frog, Cardioglossa cyaneospila, was last seen by scientists in 1949 and was feared to be extinct after decades of turmoil in the tiny East African nation, they said.
Herpetologists from the California Academy of Sciences and University of Texas at El Paso discovered a single specimen of the frog during a research expedition to Burundi in December 2011, a release from the San Francisco-based Academy reported Tuesday.
Previous knowledge of Burundi's wildlife came from scientific surveys conducted in the mid-20th century when the nation was under Belgian administration, researchers said, but its history since then has been one of political unrest, population growth and habitat loss.
Academy curator David Blackburn and Texas colleagues searched for the frog in habitats still relatively intact in the southwest part of the country.
Blackburn -- suspecting C. cyaneospila would make a call similar to possible close relatives in Cameroon -- found a single specimen on his fifth night in the forest.
"I thought I heard the call and walked toward it, then waited," Blackburn said. "In a tremendous stroke of luck, I casually moved aside some grass and the frog was just sitting there on a log. I heard multiple calls over the next few nights, indicating a healthy population of the species, but I was only able to find this one specimen."
The Bururi long-fingered frog is about 1.5 inches long, with a black and bluish-gray coloration, and males are are notable for one extra-long finger on each foot, whose purpose is unknown.