Lingnan University-Led Study Finds Lantau Horned Toad Genetically Distinct, Urges Separate Conservation Unit

The Short-legged Horned Toad (Boulenophrys brachykolos), listed as endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, is the only known small frog species in Hong Kong belonging to the genus Boulenophrys of the family Megophryidae. A study led by the Division of Science at Lingnan University has found that the Lantau Island population of the Short-legged Horned Toad shows clear genetic divergence from other local populations, along with several notable differences in the mating calls of males. The research team suggests that the Lantau population represents an early stage of speciation. Geographical isolation of Lantau Island from other landmasses likely contributed to these unique evolutionary traits. The team recommends treating the Lantau population as a separate conservation unit in future.

The Short-legged Horned Toad, an endangered species in Hong Kong, is a small frog measuring around 40 mm in length. It is characterised by short hind limbs, small horn-like projections above the eyes, and skin coloration and patterns that closely resemble dead leaves. (The photo shows the Short-legged Horned Toad population on Lantau Island.)

These findings have been published in international academic journal Current Herpetology.

The Short-legged Horned Toad is distributed across mountain streams on Lantau Island, Hong Kong Island, Kowloon, the New Territories, and adjacent Shenzhen. The research team, led by Lingnan University, collected 19 samples of the Short-legged Horned Toad (nine from Lantau Island, six from Hong Kong Island, and four from Kowloon) to examine their genetic and morphological characteristics. The results show that the Short-legged Horned Toads on Lantau form a distinct genetic group separate from those on Hong Kong Island, Kowloon, and Shenzhen. This suggests that the Lantau population has been separated from other populations for a considerable period.

The study shows that Short-legged Horned Toads are visually almost identical, making evolutionary differences difficult to detect through traditional field surveys alone. (The photo shows the Short-legged Horned Toad population on Hong Kong Island.)

In addition, the team recorded and analysed the mating calls of male Short-legged Horned Toads from Lantau Island, Hong Kong Island, and Kowloon. They found significant differences in their calls between Lantau Island and other local populations. The Lantau population produces calls with a faster rhythm and shorter individual notes.

In terms of physical appearance, the team found no marked differences between frogs from Lantau Island and other regions, indicating that physical characteristics alone may be insufficient to distinguish the Lantau population from other populations.

Prof Jonathan Fong, the corresponding author of the study, Associate Dean (Administration and Education) of the Wu Jieh Yee School of Interdisciplinary Studies and Associate Professor of the Division of Science at Lingnan University.

Prof Jonathan Fong, the corresponding author of the study, Associate Dean (Administration and Education) of the Wu Jieh Yee School of Interdisciplinary Studies, and Associate Professor of the Division of Science at Lingnan University, said the study provides a more comprehensive approach to evaluating evolutionary divergence among populations of the same species. He said, “Many amphibians look very similar, making evolutionary differences difficult to detect through traditional methods by examining morphology alone. By integrating genetic and acoustic data, we found that frogs on Lantau Island have distinct genetic make-up and male toads have different mating calls. This suggests that Lantau population is following a distinct evolutionary trajectory.”

Prof Sung Yik-hei, the first author of the study and Adjunct Assistant Professor of the Division of Science at Lingnan University.

Prof Sung Yik-hei, the first author of the study and Adjunct Assistant Professor of the Division of Science at Lingnan University, explained that Lantau Island became geographically isolated from the mainland approximately 10,000 years ago. The geographical isolation likely reduced gene flow between populations, allowing the Lantau Short-legged Horned Toad population to develop unique genetic traits over time. The study also highlights that Hong Kong may harbour undiscovered biodiversity.

Researchers conduct fieldwork in Hong Kong. (Click here to listen: Audio comparison of the calls of the Short-legged Horned Toad population in Lantau Island and the Kowloon population.

Prof Sung said, “The results suggest that the Short-legged Horned Toad population on Lantau Island may represent an early stage of speciation, although current evidence is insufficient to determine whether the Lantau population constitutes a distinct species. The Short-legged Horned Toad is an endangered species, and if the Lantau population declines or become extinct, its unique genetic traits could be lost and irreplaceable by populations from other areas. We therefore propose that conservation management recognise the Lantau population as an independent conservation unit, giving due consideration to its specific conservation needs to ensure the survival of this unique native population.”

Co-authors of the study include Franco Leung Ka-wah, PhD student at James Cook University in Australia, and Mr Henry Chan Man-ho, Senior Project Officer at Outdoor Wildlife Learning Hong Kong. The research was supported by funding from the Lantau Conservation Fund.

For the full study, please visit: Intraspecific Diversity of Short-Legged Horned Toad (Boulenophrys brachykolos) in Hong Kong: Identification of a Distinct Conservation Unit on Lantau Island

Lingnan University and the Civil Service Bureau of the Hong Kong Special Administrative Region (HKSAR) Government jointly organised the first Government Career Fair on the Lingnan campus today (29 September), with 20 exhibition booths, bringing together over 15 government bureaux and departments — including the Digital Policy Office, the Education Bureau, disciplined services and the Leisure and Cultural Services Department, totalling over 30 civil service grades. Recruitment activities were held alongside career talks, on-site interviews, and written examinations, helping students gain a deeper understanding of the career development opportunities available across different government grades.

Mrs Ingrid Yeung Ho Poi-yan, Secretary for the Civil Service, visited the Lingnan campus and the Fair, accompanied by Prof S. Joe Qin, President and Wai Kee Kau Chair Professor of Data Science at Lingnan University, Prof Raymond Chan Hon-fu, Vice-President (Academics) cum Provost and Lam Man Tsan Chair Professor of Scientific Computing, and Mr Bernard Wu Tak-lung, Chairman of the Career Development Committee. She spoke with representatives from the government bureaux and departments, as well as University staff and students, to learn more about the expectations and career aspirations of the younger generation regarding government careers.

Mrs Ingrid Yeung Ho Poi-yan, Secretary for the Civil Service, tours the Lingnan campus and Career Fair, accompanied by Prof S. Joe Qin, President and Wai Kee Kau Chair Professor of Data Science at Lingnan University, Prof Raymond Chan Hon-fu, Vice-President (Academics) cum Provost and Lam Man Tsan Chair Professor of Scientific Computing, Mr Bernard Wu Tak-lung, Chairman of the Career Development Committee, and Ms Irene Ng Wai-ming, Director of Student Affairs. Mrs Yeung also speaks with representatives of government bureaux and departments, as well as University staff and students, to learn more about the expectations and career aspirations of the younger generation regarding government careers. Photo source: Lingnan University

Mrs Yeung said, “The Government encourages young people with aspirations for public service to join the civil service. Through direct exchanges with students at Lingnan University, government departments help students gain a deeper understanding of the wide range of career opportunities available in the Government and facilitate their early career planning. The Government will continue to offer graduates from diverse academic backgrounds broad career development opportunities, enabling them to apply their professional knowledge and expertise in serving the public.”

President Qin said, “Since the 2024/25 academic year, Lingnan University has made generative artificial intelligence (AI) a compulsory common core course for all first-year students, enabling them to develop AI and digital capabilities while cultivating their critical thinking abilities. These students have now entered their third year of study, at a time when the HKSAR Government is actively promoting ‘AI+’ development, offering opportunities for young people equipped with digital capabilities and a wish to serve the community through public service. Gaining exposure to the civil service before graduation allows students to apply what they have learned in real-world settings and encourages them to think at an earlier stage about how technology can be used to respond to the needs of society.”

Students participating in the event welcomed the opportunity to gain a deeper understanding of the work scope of different government bureaux and departments and their talent needs, as well as how their academic backgrounds and skills can be applied in public administration and community services. Through direct exchanges with representatives from various government bureaux and departments, students were able to learn more about career development prospects, recruitment arrangements, and job vacancies in the civil service, and gained deeper insight into the important responsibilities that the civil service team shoulders in serving the community and supporting the HKSAR’s long-term development.

The Office of Student Affairs at Lingnan University said that the University will continue to strengthen collaboration with government departments, businesses, and all sectors of the community to actively expand opportunities for students, and provide more diversified employment support and talent development initiatives to help them make a smooth transition from university to the workplace. Lingnan will continue to fulfil the important role of higher education in nurturing talent, and cultivating graduates with an international outlook, an innovative spirit, and a strong sense of social responsibility, thereby injecting new impetus into the future development of the HKSAR.

Lingnan University and the Civil Service Bureau of the HKSAR Government jointly organise the first Government Career Fair. Photo source: Lingnan University