Six New Clawed Frogs Found In Africa Shed Light On "Lost Ancestor"

Six new frog species known as clawed frogs were recently found in Central and West Africa. A Canadian-led science team discovered the relatively small frogs – only about five centimeters long – in stagnant and slow-moving waters, which the species seems to prefer.

"Because the African clawed frog is used as a model organism for biological research, it would be understandable to think that scientists had already pinned down the number of species and other aspects of their diversity, such as where they live and how they are related to one another," Ben Evans, lead author of the study and an associate professor in the Department of Biology at McMaster University, explained in a news release. "But this isn't the case."

Researchers stumbled upon the new species during a hunt for the mysterious "lost ancestors" of some of their close cousins. African clawed frogs are polyploid organisms, meaning their DNA doubled during evolution, giving them a redundant copy of every gene.

Compared to these rather unique frogs, most animals, including humans, are diploid, which means they have two sets of chromosomes: half from their mother and half from their father. Instead, a clawed frog gets all its mother's and father's genes. What's remarkable about the recent find is that this genome duplication has occurred several times in the new species, a process responsible for four individuals that are tetraploid species (having four sets of chromosomes) and two that are dodecaploid species (having 12 sets).

To distinguish between the seemingly-identical flat-bodied frogs, researchers collected voice recordings, preformed CT scans of their internal anatomy and DNA and conducted chromosome analyses. 

"For biodiversity conservation, it is paramount that we understand how much diversity there is and where it occurs," Evans added. "This is particularly crucial in the tropics, where global biodiversity is highest and in groups of organisms that have subtle physical differences between species and in which species diversity is therefore 'cryptic'."

Other interesting characteristics of these frogs include vocal organs that can produce sound underwater, and the claws on its first three toes, for which they are named. These frogs are also carnivorous scavengers that will eat anything they can dig their claws into. They rely on extremely sensitive fingers and an acute sense of smell to locate food, though they are known for attacking anything that passes in front of them.

Researchers plan to travel to Ghana next year in search of more genetic information and the "lost" independent species that merged and gave rise to these recently discovered ones. The study's findings were recently published in the journal PLOS ONE.

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