Herpetologists from the California Academy of Sciences and the University of Texas at El Paso discovered a single specimen of the Bururi long-fingered frog (Cardioglossa cyaneospila) during a research expedition to Burundi in December 2011. The frog was last seen by scientists in 1949 and was feared to be extinct. Burundi sits at an intriguing geographic crossroads, bordering the vast Congo River Basin, the Great Rift Valley, and the world’s second largest freshwater lake, Lake Tanganyika.  Academy curator David Blackburn, PhD, joined his colleague Eli Greenbaum, PhD, assistant professor of biological sciences at UTEP, on the 2011 expedition to find Cardioglossa cyaneospila, as well as other amphibians and reptiles first described 60 years ago. On his fifth night in the forest, Blackburn finally found a single specimen.

“I thought I heard the call and walked toward it, then waited,” said Blackburn. “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.  The males are notable for one extra-long finger on each foot, analogous to the “ring finger” in humans, whose purpose is unknown. Its closest relatives live in the mountains of Cameroon, more than 1,400 miles away. 

The lone specimen collected, which now resides in the Academy’s herpetology collection, can be used for DNA studies to determine how long the Cardioglossa species from Burundi and Cameroon have been genetically isolated from one another. The results will shed light on Africa’s historical climate conditions, a topic that has far-reaching implications for understanding the evolution of life in the continent that gave rise to our own species.

In addition to locating the Bururi long-fingered frog, Blackburn and Greenbaum also documented dozens of other amphibians in Burundi, many of which had never before been recorded in the country. The team also discovered some species that may be new to science.

“Eventually, we will use the data from our expedition to update the (International Union for Conservation of Nature and Natural Resources) conservation assessment for amphibians of Burundi,” Greenbaum said. “Because Burundi is poorly explored, we’ve probably doubled the number of amphibian species known from the country. Once we demonstrate that Burundi contains rare and endemic species, we can work with the local community to make a strong case for preserving their remaining natural habitats.”

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Click on the below image to read about Dr. Greenbaum's 2011 re-discovery in the Congo of four long-lost frog species.