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Critically endangered species on the brink: Du Toit's torrent frog

There have been numerous surveys to locate Du Toit’s torrent frog since its last record in 1962, but all attempts have failed to find the species.

Scientists from the Natural History Museum and ZSL (Zoological Society of London) are part of a new study looking into the potential extinction of Arthroleptides dutoiti, or Du Toit’s Torrent frog. Known to be currently Critically Endangered by the IUCN Red List, Du Toit’s Torrent frog is a priority species on ZSL’s EDGE (Evolutionarily Distinct and Globally Endangered) amphibians list, given its Red List status and phylogenetic distinctiveness. There have been numerous surveys to locate Du Toit’s torrent frog since its last record in 1962, but all attempts have failed to find the species.

Du Toit’s Torrent frog is endemic to Mount Elgon in East Africa, on the borders Kenya and Uganda. They have interesting biological features adapted to living in and around fast flowing streams. Tadpoles have mouthparts adapted to rasping and attaching themselves to rocks, preventing them being ‘flushed down mountain streams’ and adults also have t-shaped fingertips, presumably to improve their grasping ability on slippery rocks.

Co-author Dr Simon Loader, Principal Curator in Charge of Vertebrates at the Natural History Museum has said: ‘There are only three species in the genus that Du Toit’s Torrent frog belongs to with closest relatives to this genus found in central Africa. These frog lineages are estimated to be separated for many millions of years. If you lose these lineages, you lose a large amount of evolutionary history and that’s what makes them important. It’s not just losing a species, it’s losing a particular branch of the evolutionary tree, which we believe to be quite distinct. Du Toit’s Torrent frog IUCN Red List conservation status will be re-assessed in light of these new findings and are likely to change from being critically endangered to being extinct’.

Dr Loader and colleagues were able to highlight the worrying decline in this species by combining information from the 1930s, work from the 1960s (Ronalda Keith, AMNH) and ongoing work from the National Museum of Kenya (NMK) to find Du Toit’s Torrent frog. Over the last 20 years colleagues from NMK, including from first author of the scientific paper Jacob Mueti Ngwava, have carried out numerous field surveys to find this specific frog, sadly to no avail. This decline could be due to many factors including the logging of the forests and the conversion of its habitat to farmland. The authors believe the species is no longer present in Kenya but there may a chance that the species could be found on the Ugandan side, where surveys haven’t been less intensive.

ZSL's EDGE Programme Manager, Olivia Couchman, said: ‘The potential loss of the Du Toit's Torrent frog from Africa's Mount Elgon, which has not been seen since the 1960s, would mean the loss of many million years of evolutionary history - there is quite simply no other species like it on the planet.’

The paper is published in African Journal of Herpetology on 14 May 2021.


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About the Natural History Museum:

The Natural History Museum is both a world-leading science research centre and the most-visited natural history museum in Europe. With a vision of a future in which both people and the planet thrive, it is uniquely positioned to be a powerful champion for balancing humanity’s needs with those of the natural world.

It is custodian of one of the world’s most important scientific collections comprising over 80 million specimens. The scale of this collection enables researchers from all over the world to document how species have and continue to respond to environmental changes - which is vital in helping predict what might happen in the future and informing future policies and plans to help the planet.

The Museum’s 300 scientists continue to represent one of the largest groups in the world studying and enabling research into every aspect of the natural world. Their science is contributing critical data to help the global fight to save the future of the planet from the major threats of climate change and biodiversity loss through to finding solutions such as the sustainable extraction of natural resources.

The Museum uses its enormous global reach and influence to meet its mission to create advocates for the planet - to inform, inspire and empower everyone to make a difference for nature. We welcome over five million visitors each year; our digital output reaches hundreds of thousands of people in over 200 countries each month and our touring exhibitions have been seen by around 30 million people in the last 10 years.

ZSL’s EDGE of Existence programme

ZSL’s EDGE of Existence programme is the only global conservation initiative to focus specifically on threatened species that represent a significant amount of unique evolutionary history. Using a scientific framework to identify the world’s most Evolutionarily Distinct and Globally Endangered (EDGE) species, the EDGE of Existence programme highlights and protects some of the most unique and most wonderful species on the planet. EDGE species have few close relatives on the tree of life and are often extremely unusual in the way they look, live and behave, as well as in their genetic make-up. They represent a unique and irreplaceable part of the world’s natural heritage, yet an alarming proportion are on the verge of extinction.

What is EDGE? | EDGE of Existence

ZSL (Zoological Society of London)

Founded in 1826, ZSL (Zoological Society of London) is an international scientific, conservation and educational charity whose mission is to promote and achieve the worldwide conservation of animals and their habitats. Our mission is realised through our ground-breaking science, our active conservation projects in more than 50 countries and our two Zoos, ZSL London Zoo and ZSL Whipsnade Zoo. For more information visit