Miniature odorous frog discovered in southern Vietnam

Researchers have identified a new miniature frog species, Odorrana chumu, from Vietnam’s Langbian Plateau. The find matters because the frog appears highly restricted in range and adds evidence that the region holds underestimated amphibian diversity that may need stronger protection.

Why it matters: - Odorrana chumu adds a new species to a genus already known for taxonomic complexity and hidden diversity. - The frog’s apparently limited range on the Langbian Plateau raises conservation concerns. - The discovery strengthens evidence that southern Vietnam’s montane forests still hold undocumented amphibian endemism.

What happened: - Researchers described Odorrana chumu sp. nov. from Dak Lak Province on the Langbian Plateau in southern Vietnam. - The study used integrated morphological and molecular evidence. - The paper was published online on 15 October 2026 in Asian Herpetological Research. - The DOI is 10.3724/ahr.2095-0357.2026.0048. - The research involved scientists from the Kunming Institute of Zoology, Chinese Academy of Sciences; the Vietnam Academy of Science and Technology; the Australian Museum; the University of New South Wales; and the North Carolina Museum of Natural Sciences.

The details: - Adult males measure 29.1–31.8 mm in snout–vent length, with a mean of 30.2 ± 0.89 mm. - That mean is the smallest among the 71 recognized Odorrana species. - The frog has a greatly enlarged tympanum, with a tympanum-to-eye diameter ratio of 0.81 ± 0.07. - The tympanum–eye distance is 0.5 ± 0.11 mm. - The species is diagnosable by a very small body, a head longer than wide, a distinct dorsolateral fold, vomerine teeth, a bilobate subgular vocal sac, and a bicolored iris with a coppery horizontal band. - The species also shows finger length III > IV > II > I, no webbing between the fingers, webbed toes with formula I0–0II0–0III0–1IV1–0V, and a distinct nuptial pad on finger I. - Researchers collected six adult males and compared them with related species. - Principal component analysis of 22 morphological characters separated adult males from O. absita, O. montivaga, and O. khalam. - The first two principal components explained 52.9% of total variation. - Males differed significantly from O. absita in 10 of 22 characters, from O. montivaga in 17, and from O. khalam in 19. - Mitochondrial 16S rRNA analysis placed the species in the O. montivaga group. - The new species formed a well-supported clade sister to O. absita and O. montivaga. - Mean uncorrected p-distances were 8.2% from O. absita, 6.9% from O. montivaga, and 8.7% from O. khalam. - The study generated the first molecular sequences for O. montivaga. - Specimens were found at night on rocks and leaves along a stream in evergreen forest at 674–683 meters above sea level. - O. montivaga occurs above 1,000 meters.

Between the lines: - The Odorrana genus spans India, Southeast Asia, southern China, and Japan, and its wide range has made species boundaries difficult to resolve. - Morphological similarity has already complicated the group, including the reclassification of Odorrana gigatympana as a junior synonym of O. absita. - The authors said the Langbian Plateau remains an isolated montane center of amphibian endemism. - The authors also said diversity in the O. montivaga group across southern Vietnam is still substantially underestimated. - The species’ miniaturized body and oversized tympanum make it especially distinctive within the region’s fauna. - The habitat lies within the Deo Ca Forest area, about 150,000 hectares managed as five separate watershed protection areas despite high biodiversity and ongoing discoveries. - The findings also support the idea that the Langbian and Kon Tum–Gia Lai plateaus may hold distinct biogeographic assemblages.

What’s next: - The authors said the new species warrants a conservation assessment because its known range appears restricted. - Further surveys are needed for females and additional populations. - Integrative work is needed to clarify species boundaries and evolutionary relationships across the Langbian and Kon Tum–Gia Lai plateaus. - The findings support stronger protection and targeted amphibian conservation planning in the region.

The bottom line: - Odorrana chumu is a tiny, highly distinctive frog that points to still-uncounted amphibian diversity in southern Vietnam and a need for faster conservation action.