In the heart of the Hainan Tropical Rainforest National Park, scientists stumbled upon what was previously considered an ordinary frog from a Vietnamese group. It turned out to be a completely different species — Rana hainan, or the Hainan groove-toed frog. The discovery, published in 2026 in the journal ZooKeys, was the result of three years of field work and showed how thoroughly even well-protected territories need to be studied.
Researchers from Hainan Normal University, together with colleagues from Shenyang and Sun Yat-sen universities, worked in the area of Diaoluo Mountain and in the Shangxi Provincial Nature Reserve. They collected samples at elevations from 350 to 950 meters among evergreen broadleaf forests, where ferns and shrubs grow under the canopy and streams flow over rocky beds. The frogs breed in seasonal pools and quiet stream pools.
Molecular analysis of mitochondrial genes and a detailed comparison of morphology confirmed that the individuals form a separate evolutionary lineage with noticeable genetic differences from their closest relatives. The new species has a characteristic triangular black mark on the temporal region, narrow straight folds along the back, and a special structure of the toes with grooves. During the breeding season, males have a continuous grayish-white nuptial pad on the first finger.
The Hainan Tropical Rainforest is one of the best-preserved massifs of this type in China. The complex terrain, diverse vegetation, and network of streams create conditions in which species found nowhere else can hide. The discovery of an endemic precisely here underscores the role of the national park as a genuine reservoir of biodiversity, and not merely a beautiful territory.
So far, Rana hainan is known only from two protected areas. Its narrow range makes the species vulnerable to any environmental changes — from logging to climate change. At the same time, the very existence of such a discovery shows that systematic surveys of nature reserves continue to yield new data even in the twenty-first century.
Every such discovery is a reminder: nature conservation is not only about saving already known species, but also about giving a chance to those we have not yet managed to notice.
