Conservation news

New ‘Elfin mountain toad’ discovered in Annamite Mountains of Vietnam

  • A team of Russian and Vietnamese researchers described Ophryophryne elfina, the Elfin mountain toad, in the journal ZooKeys last month.
  • The toad, one of the smallest species of horned mountain toads ever described to science, was given the name Ophryophryne elfina, which roughly translates to “elfish eyebrow toad” — and the researchers who made the discovery say that there is evidence to suggest that the species could already be considered endangered.
  • The species name “elfina,” of course, derives from the English word “elf,” small, magical forest creatures found in German and Celtic folklore.

A new species of Asian mountain toad belonging to the genus Ophryophryne has been discovered in the the Truong Son or Annamite mountains of Vietnam, an area of high diversity for the group.

The toad, one of the smallest species of horned mountain toads ever described to science, was given the name Ophryophryne elfina, which roughly translates to “elfish eyebrow toad” — and the researchers who made the discovery say that there is evidence to suggest that the species could already be considered endangered.

A team of Russian and Vietnamese researchers described Ophryophryne elfina, the Elfin mountain toad, in the journal ZooKeys last month.

The species name elfina, of course, refers to elves — small, magical forest creatures found in German and Celtic folklore. The new toads have horn-like projections above their eyes and are as diminutive as their namesake: at around three centimeters in length, they are the smallest known species of the genus Ophryophryne.

The researchers were also inspired by the toad’s unique habitat when devising the species name. The Elfin mountain toad lives in highland wet subtropical evergreen forest on mountain summits at elevations higher than 1,800 meters (about 5,900 feet) or on the slopes of the eastern side of Langbian Plateau, which lies in the southern Annamite Mountains. “Both the rocks and the dwarf curbed trees are covered with a heavy layer of moss, whilst a thick misty fog is constantly lingering amongst the trees,” the researchers note in a statement announcing the discovery. “This is why such wet mountain ecosystems are known as elfin forests.”

Paratypes of Ophryophryne elfina sp. n. in life. A–D Bidoup Mt., Bidoup–Nui Ba N.P., Lam Dong Prov., 2000 m a.s.l.: A ZMMU A-4788 (field number NAP-01449), male, dorsolateral view B ZMMU A-4788 (field number NAP-01455), female, dorsolateral view C ZMMU A-4788 (field number NAP-01449), male, ventral view D ZMMU A-4788 (field number NAP-01455), female, ventral view E–F Chu Yang Sin Mt., Chu Yang Sin N.P., Dak Lak Prov., 1800 m a.s.l.: E ZMMU A-5691 (field number ABV-00580), metamorph, dorsolateral view F ZMMU A-5691 (field number ABV-00581), metamorph, dorsolateral view. Photos by N.A. Poyarkov. Image via Poyarkov Jr et al. (2017) doi:10.3897/zookeys.672.10624.

The Elfin mountain toad is now one of three Ophryophryne species known to inhabit the Langbian Plateau. While all three share the same habitat, however, they are easily identified by their advertisement calls, which resemble whistling birds, according to the researchers.

In addition to describing the new species in ZooKeys, the researchers also examine the distribution of its two closest relatives.

“A hidden diversity of Ophryophryne frogs is revealed in the mountains of the Langbian Plateau, where previously only one species, O. gerti, was correctly reported,” the researchers write in ZooKeys. “In our study it is shown that the previous records of O. cf. gerti from central Vietnam and Laos (Ohler 2003, Bain et al. 2007) actually belong to different species of Ophryophryne and thus we clarify the range of O. gerti showing that this species is likely endemic to the Langbian Plateau. The known distribution of O. synoria is also extended, previously known exclusively from Cambodia (Stuart et al. 2006) and adjacent provinces of Vietnam (Vassilieva et al. 2016), and demonstrate that this species has a considerably wider range encompassing the central, northern and western edges of the Langbian Plateau.”

O. elfina is endemic to the northern and eastern edges of the plateau, the researchers found. Like all toads of the genus Ophryophryne, they depend on clean, fast-flowing mountain streams to reproduce and “appear to be restricted to relatively undisturbed broadleaf evergreen forests,” the researchers note. As range-restricted habitat specialists, they are therefore at considerable risk due to deforestation and other destructive changes to their habitat.

“The Langbian Plateau is known for its high herpetofaunal diversity and endemism, a significant portion of which has been discovered only recently,” the researchers write. “Despite this increase in species discoveries, many areas of the Annamites have received little scientific attention and are very likely to host further previously unknown diversity. The need for biological exploration in this region is made more urgent given the ongoing loss of natural habitats due to logging, road construction, increasing agricultural pressure and other human activities.”

Holotype of Ophryophryne elfina sp. n. in life (ZMMU A-5669, male, field number NAP-02658), dorsolateral view. Photo by N.A. Poyarkov.

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