International expedition discovers new species of frog from Vietnam

by ZSL on

In September 2017, ZSL joined an international team to climb Mount Ky Quan San, the second highest mountain in Vietnam. This team did not climb the mountain to gain spectacular views of the rugged scenery, but rather to look for Critically Endangered frogs.

In 2015, ZSL began collaborating with Hoang Lien National Park, the Australian Museum and the Asian Turtle Program of Indo Myanmar Conservation. Our work has been focussed on one of southeast Asia’s most imperilled amphibian faunas in the Hoang Lien Range in northern Vietnam. Whilst there are many threatened frogs in this part of the world, much of our effort has targeted Botsford’s Leaf-Litter Frog, a Critically Endangered EDGE species that is endemic to Mount Fansipan, Vietnam’s highest mountain, approximately 20 km south of Mount Ky Quan San.

Close-up photograph of the Botsfords’s leaf-litter frog clinging to a leaf
Botsfords’s leaf-litter frog

The purpose of our 2017 expedition was to see if Botsford’s Leaf-Litter Frog was present at other places in the Hoang Lien sites, specifically the higher elevations of Mount Ky Quan San. We began on foot and walked through picturesque terraced rice fields surrounded by jagged mountains, the first 10 minutes were pleasant but then we began a very steep, face-reddening climb out of the valley and into the forest along narrow paths clogged with thick mud. The trek was pretty tough, and we were conscious not to look up at the ominous mountain towering above us; there was still so far to go before we even reached its base. After several hours, adventurous river crossings on rickety bridges and logs we began the true ascent. We slogged a gruelling zig-zag path up the side of the mountain until we reached a flatter area with a large hut which would be our camp for the night.

terraced rice fields

Before we could even think about sleep, we had our long-anticipated first night of field work on Mount Ky Quan San. We waited until it was dark and trekked part of the way back down the mountain where we had seen a promising looking stream and began to search for frogs - it didn’t disappoint! 

Vivid green sucker frogs, pompous looking fire bellied toads and a lot of horned frogs. We returned to camp in the early hours and the following morning we continued our hike. It soon became apparent the previous day had just been the warmup - the next leg of the hike involved a frantic scramble over boulders, crawling across muddy ridges and using wet vegetation to haul ourselves up the misty mountain. 

With shaking legs and trembling hands, we finally reached our target elevation of 2800m and we were buffeted by a biting wind as we made camp. The word ‘camp’ is almost deceiving, the reality being a tarpaulin draped over a rope on a steep hillside. It was freezing, our teeth were chattering and we squatted around a smoky fire for warmth whilst we waited eagerly for that much needed coffee to boil. Man pitching tent

The habitat on the mountain was disappointingly degraded. Many trees had been hacked to pieces for fuelwood and the remaining vegetation overgrazed by goats. The forest on this mountain must have been incredible not so long ago. As darkness fell, we eventually found a beautiful stream surrounded by gnarled trees covered in thick blankets of moss. We walked the length of the stream, knee deep in the freezing water trying to pick out frogs and their reflective eye shine in the beams of our powerful headlamps. We were careful with where we put our hands, as we had seen several chunky vipers on our way down to the stream. 

This small patch of forest was teaming with horned frogs, they emitted loud quack like calls in the miserable drizzle. We diligently recorded these calls as these data would be important if we were to confirm the identity of these frogs. We suspected that these horned frogs were Mount Fansipan horned frogs, a species we were already in the process of describing as new but as many horned frogs look so similar, we couldn’t be sure. Whilst we encountered a couple of Hoang Lien Leaf-Litter Frogs, and some beautiful treefrogs we finished our survey a little disappointed. 

Our target species, Botsford’s Leaf-Litter Frog, was notably absent. That night was one of the most uncomfortable nights any of us have ever spent in the field, the ground was wet and cold and, due to the camp site being on a steep slope, we kept sliding down the hill in our sleeping bags. The rain trickled in over the groundsheet, saturating our sleeping bags and after what felt like the longest night ever we woke up in a grumpy huddle. None of us could wait to get off the cold ridge and into the hut we had slept in the night before. 

Several months after the trip we had some exciting news. The Australian Museum team had sequenced some of the samples we had collected on Mount Ky Quan San. The results demonstrated that two horned frogs we had previously described were present on the mountain (the Red-Thighed Horned Frog and the Hoang Lien Horned Frog), but surprisingly the genetic data showed that what we had suspected to be the Mount Fansipan Horned Frog was, in fact, a new species!

red frog on green background

We began what turned out to be an arduous three-year process of describing this species. Describing this particular species was very difficult as the morphology was almost identical to the Mount Fansipan Horned Frog and the call was almost the same too (although the new species likely calls at a different time of year). Whilst the molecular data indicated that this population of frogs was distinct, it took painstaking analysis and days of work to compile enough information using multiple lines of evidence in order to describe this species, the Mount Ky Quan San Horned Frog, as new. 

We gave this frog the scientific name of Megophrys frigida after the cold conditions of the site where we collected it. 

This is the fourth species of horned frog described by our team. We expect that this, like the three others we have described, will qualify for being assessed as Endangered by the IUCN as it is highly likely that is restricted to just a small part of the Hoang Lien Range in northern Vietnam and there is ongoing habitat loss and degradation in the small area in which it occurs. 

It is vital that more work is undertaken to understand the distribution and natural history of this new and little known brown frog. Despite the hardship of the 2017 expedition, we can’t wait to go back!

team of conservationists


We are extremely grateful to the staff at Hoang Lien National Park and Bat Xat Nature Reserve for their assistance and collaboration. This work was supported by the Ocean Park Conservation Foundation Hong Kong, an Australian Museum Research Institute Visiting Fellowship and by The EDGE of Existence Programme and the IRC-Marie Skłodowska-Curie CAROLINE Fellowship.

Blog authors
  • Benjamin Tapley, Curator of Reptiles and Amphibians, Zoological Society of London
  • Luan Thanh Nguyen, Botsford’s leaf-litter frog EDGE Fellow, Asian Turtle Program / Indo Myanmar Conservation
  • Jodi Rowley, Curator of Amphibian & Reptile Conservation Biology at the Australian Museum and UNSW
  • Stephen Mahony, University College Dublin / The Natural History Museum
  • Hao Van Luong, Hoang Lien National Park

Tapley, B., Cutajar, T., Nguyen. L.T., Portway, C., Mahony, S., Nguyen, C.T., Harding, L., Luong, H.V., Rowley, J.J.L. In Press. A new potentially Endangered species of Megophrys from Mount Ky Quan San, northwest Vietnam. Journal of Natural History. In Press.

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