The Saga Of The Long-Fingered Frog
March 28, 2012

The Saga Of The Long-Fingered Frog

A single specimen of the Bururi long-fingered frog has been discovered by herpetologists from the California Academy of Sciences and the University of Texas at El Paso. The researchers discovered the Bururi frog while on a research expedition to Burundi in December 2011. This frog had been considered long since extinct, as the last time it had been seen by scientists was in 1949.

Burundi is a place of interest for biologists who study the evolution and distribution of life in Africa. Sitting at a crossroads between the Congo River Basin, the Great Rift Valley and the world´s second largest freshwater lake, Lake Tanganyika, Burundi provides these biologists with plenty of insights into how life began and how it has traveled.

Political unrest, population growth and habitat loss however, has kept researchers and biologists from being able to closely study Burundi and its rich evolutionary history. Today, Burundi has one of the highest population densities in Africa with approximately 10 million people living in an area roughly the size of Massachusetts.

Academy curator David Blackburn and his colleague Eli Greenbaum, professor at the University of Texas El Paso embarked on the 2011 expedition with the expressed intent to find the Bururi frog, as well as other reptiles and amphibians described more than 60 years ago in previous expeditions. The biologists were pleased to find the habitats of the Bururi Forest Reserve relatively intact, with populations of rare birds and chimpanzees present.

To find the Bururi frog, Blackburn looked to the call of a possible relative in Cameroon. As the call of the Bururi frog had not been documented, Blackburn had only a hunch the two calls would be similar to lead him to the Bururi. His suspicions proved to be correct and on the fifth night of the expedition, he found his frog.

“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 black and bluish long-fingered Bururi frog is about 1.5 inches long. These frogs get the name “long-fingered” from the extra long toe on the male Bururi frog. This toe is analogous to the ring finger in humans, though its purpose is still unknown. As Blackburn discovered, the Bururi shares its call with its closest Cameroon relatives, who live more than 1,400 miles away.

Detecting such a healthy population Blackburn and Greenbaum collected a single species of Bururi frog to conduct genetic testing. These studies should shed some light on how distant the Bururi and Cameroon frogs are from one another, genetically speaking. With this information, Blackburn and Greenbaum hope to explain the history of Africa´s climate conditions. The frog now lives in the Academy´s herpetology collection.

Blackburn and Greenbaum´s research is on-going, and they hope to further document amphibian and reptilian species in the African region of Burundi. Greenbaum told the California Academy. “Eventually, we will use the data from our expedition to update the IUCN conservation assessment for amphibians of Burundi,” said Greenbaum. “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.”