Nav: Home

Scientists solve lingering mystery of poorly understood frog

September 11, 2019

An international team of scientists, led by researchers at McMaster University, has solved a centuries-old mystery of 'Fraser's Clawed Frog', an unusual and elusive species found in West Africa.

The findings, published today in the journal PLOS ONE, dispel previous myths and shed new light on Xenopus fraseri including its geographic origin, evolutionary relationships, ecology, and distinctive species traits.

Two specimens of the frog, with a distinctive combination of four claws on the hind legs as well as small bony protrusions on the roof of their mouths known as vomerine teeth, were collected by British zoologist Louis Fraser in 1852 and housed at the Natural History Museum (NHM) in London.

In 1905, Fraser's clawed frog was designated as a distinct species, but its place on the evolutionary tree, geographic distribution, and ecology has since stumped scientists --due to a lack of genetic samples and poor records of its origin.

"The ancient condition of the only two specimens available to us posed many challenges for understanding its distinctiveness using DNA and knowing exactly where they came from" explains Ben Evans, lead author of the study and a professor of biology at McMaster University.

"The accurate identification of species is so important because it allows us to study change in populations, better understand how evolution occurs, and explore the processes that drive diversification, extinction and adaption," he says.

The team, which included researchers from the NHM, the Max Planck Institute in Germany and the University of Florida, used sensitive techniques -similar to approaches used to sequence the genomes of Neanderthals--to sequence the mitochondrial genome from the delicate specimens.

In addition, scientists sequenced complete or nearly complete mitochondrial genomes from 29 other Xenopus species, used high-resolution CT scanning to compare the internal and external anatomy of these and other specimens and, through intensive field work, managed to collect additional specimens of Fraser's frog in several remote regions of West Africa.

By doing so, they determined Fraser's Clawed Frog was indeed distinct from all others. And while it was previously thought to have lived in lowland tropical forests in West Africa, researchers found it actually inhabits the relatively hot and arid regions of northern Cameroon and northern Ghana.

"Obtaining DNA from specimens that have been preserved in spirit for well over a hundred years is something that has only become achievable in the last few decades. The recent advances in DNA extraction and sequencing are allowing us to revisit specimens and challenge assumptions made in the past," says Jeff Streicher, senior curator of amphibians and reptiles at the NHM.

In the summer of 2020, the team plans to travel to Nigeria to continue their efforts to understand biodiversity and genome evolution of African clawed frogs.
-end-


McMaster University

Related Science Articles:

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
AAAS and March for Science partner to uphold science
AAAS, the world's largest general scientific organization, announced Thursday that it will partner with the March for Science, a nonpartisan set of activities that aim to promote science education and the use of scientific evidence to inform policy.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...