Rare mouth brooding frog could possibly be extinct

Former EDGE fellow Claudio Soto-Azat has recently published a paper on the conservation of Darwin’s frogs, which includes the northern Darwin’s frog (Rhinoderma rufum) – EDGE amphibian 45. The work carried out as part of his fellowship programme and his PhD at the Universidad Andres Bello in Chile has revealed that the species may no longer exist.

Whilst there are numerous species named after the English naturalist Charles Darwin, two of the most incredible are frogs found in Chile and Argentina. The northern (Rhinoderma rufum) and the southern Darwin’s frog (Rhinoderma darwinii) are unique amongst all other amphibians as they are the only species where the males incubate the eggs of their young in their vocal pouch. These species are incredibly unique and also extremely endangered. As the northern Darwin’s frog is listed as critically endangered it was calculated to be EDGE amphibian number 45. Recent research by an EDGE fellow revealed that Rhinoderma rufum might actually be extinct.

The work was carried out by Claudio Soto-Azat, and his collaborators (including Andrew Cunningham and Marcus Rowcliffe from ZSL) and published last week in the journal PLoS ONE as part of his two year EDGE fellowship programme and his PhD on the temperate forests of South America. By using museum specimens and records it was possible to develop historical distribution maps for both species. Surveys were then carried out to understand the current populations and change in distribution. Whilst the southern Darwin’s frog was found in only 36 sites in Chile and Argentina, its northern sister species was never sighted.

Map depicting range of Darwin's frog species

As the northern Darwin’s frog has not been sighted since October 1980 the authors of the paper suggest that it is probably extinct – they go on to state that based on modelling it is likely to have gone extinct in 1982. Hope remains that a small population of R. rufum still exist based on the vast historical distribution of the species in the past. Therefore it is suggested that the species retains its red list IUCN status of Critically Endangered, but to be tagged with the Possibly Extinct subcategory.  It is also proposed that R. darwinii should be reclassified from Vulnerable to Endangered as remaining populations are very small and severely fragmented. We hope this information is considered when the next IUCN conservation assessment takes place.

If the northern Darwin’s frog is extinct it would represent a huge loss in genetic diversity and their unique reproductive behaviour will be lost forever. “The EDGE programme and the Institute of Zoology, Zoological Society of London, have been the most important support I have had to carry out my research. Not only due to funding, but also since the important contribution of ZSL scientists and conservation specialists this study was possible”, says Claudio Soto. This highlights the importance of the EDGE of existence programme and the work carried out by EDGE fellows.

The paper published in PLoS One is available here.

Read more about EDGE fellows here.


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  1. T. Caine said,

    on June 28th, 2013 at 5:21 am

    This reminds me of the Gastric-brooding frog that went extinct in Australia, also in the 1980’s. This frog was amazingly rare given that it reportedly gave birth to its offspring orally. The book “Sustaining Life” outlined how research could have potentially lead to medical discoveries on how to deal with ulcers or stomach problems, but the species went extinct before it could be done (though they are trying to clone it back to life). In either case, it underscores the importance of biodiversity and how much we stand to continue to learn from natural systems.

  2. Anonymous said,

    on July 2nd, 2013 at 8:49 pm

    Dear T. Caine,

    Thanks for your comments. Yes, the story behind the northern and southern gastric-brooding frogs (Rheobatrachus) from Australia is very similar with the situation of the northern and southern Darwin’s frogs (Rhinoderma) from Chile and Argentina. Unless we (humans) bring this species back from extinction (which sounds as a possibility now with the development of technology and availability of well preserved DNA) everything that had this species to teach us disappeared around 20 years ago. We don’t want the same happen with the mouth-brooding frogs of South America (Rhinoderma). We probably lost the northern species, but the good news is there is still time to put all our efforts to prevent the extinction of its sister southern species (R. darwinii). So, a time of several conservation challenges come.

    Best Regards,

    Claudio Soto Azat
    Former EDGE Fellow Darwin’s frogs

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