Hidden in Limestone, This New Gecko Could Disappear Before We Know It

A team of scientists has identified a new species of gecko in northern Vietnam, underscoring both the rich biodiversity and growing vulnerability of karst ecosystems across Southeast Asia.

The species, named Hemiphyllodactylus ziegleri, was discovered in Son La Province and formally described in the journal ZooKeys, February 2026. Using a combination of morphological analysis and DNA sequencing, researchers confirmed that the gecko is distinct from its closest relatives.

“This level of genetic divergence clearly indicates that we are dealing with a separate evolutionary lineage,” said L. Lee Grismer, one of the study’s co-authors.

Co-author T. Q. Nguyen added that the discovery highlights how much remains unknown about biodiversity in the region. “Karst habitats continue to yield new species, even in areas that are not completely unexplored,” he said.

What makes Hemiphyllodactylus ziegleri different from other geckos?

The newly described species is small, measuring approximately 3.8 to 4.9 centimeters in body length. It has a yellowish-gray coloration with a faint, discontinuous light stripe along its sides—subtle features that distinguish it from similar species.

More definitive differences lie in its anatomy. The researchers noted unique scale arrangements, specific toe pad structures, and the presence of precloacal pores in males, while females lack them. The species also does not possess femoral pores, a key trait used in gecko classification.

Genetically, H. ziegleri shows more than 14 percent divergence from its closest known relative, a margin considered significant enough to confirm it as a separate species.

Why are karst landscapes hotspots for new species?

Karst landscapes are formed by the dissolution of limestone over millions of years, creating caves, fissures, and isolated rocky outcrops. These fragmented environments act like ecological islands, allowing species to evolve independently.

“Each karst formation can host its own microhabitats and endemic species,” Grismer explained. “This isolation is a major driver of speciation.”

In Southeast Asia, karst ecosystems are particularly important for biodiversity. Countries such as Indonesia, Malaysia, and Vietnam are home to extensive karst regions that support a wide array of specialized flora and fauna.

However, many of these species remain undocumented due to their small size, cryptic behavior, or restricted ranges.

How threatened are karst ecosystems in Southeast Asia today?

Despite their ecological importance, karst landscapes are among the most threatened habitats in Southeast Asia. Limestone extraction for cement production is one of the primary drivers of habitat destruction.

In rapidly developing countries, karst hills are often quarried to meet construction demands. This process can completely erase entire ecosystems in a matter of years.

“Karst habitats are extremely fragile. Once destroyed, they cannot be restored within any meaningful human timeframe,” Nguyen said.

Beyond mining, infrastructure development and land conversion are also contributing to habitat loss. Roads, tourism facilities, and agricultural expansion continue to encroach on previously undisturbed areas.

Climate change adds another layer of stress. Altered rainfall patterns and temperature shifts can disrupt the delicate balance of cave and rock microclimates, affecting species that rely on stable conditions.

What does this discovery mean for conservation efforts?

The discovery of Hemiphyllodactylus ziegleri reinforces the urgency of protecting karst ecosystems before more species are lost.

Scientists warn that many organisms could go extinct before they are even documented. This is particularly true for narrowly distributed species that exist only within a single karst formation.

“Every new species we describe is a reminder of how much biodiversity is at stake,” Grismer said. “It also shows how incomplete our understanding still is.”

The study also highlights the importance of integrating genetic tools into biodiversity research. Traditional methods based solely on physical traits may overlook cryptic species that appear similar but are genetically distinct.

Are there more undiscovered species in Southeast Asia’s karst?

Researchers believe the answer is almost certainly yes.

With more than 70 known species in the genus Hemiphyllodactylus, discoveries continue to emerge at a steady pace. Many karst regions across Southeast Asia remain poorly surveyed, especially in remote or politically sensitive areas.

“Given the rate of recent discoveries, it is very likely that many more species await description,” Nguyen said.

For scientists, these findings represent both an opportunity and a race against time. Field surveys, taxonomic studies, and conservation measures must move quickly to keep up with ongoing environmental changes.

The discovery of Hemiphyllodactylus ziegleri illustrates a broader reality facing Southeast Asia’s natural landscapes. While the region remains one of the most biodiverse on Earth, it is also experiencing some of the fastest rates of environmental degradation.

Karst ecosystems, in particular, sit at the intersection of scientific value and economic exploitation.

Without stronger conservation policies and greater public awareness, many of these unique habitats could disappear—along with the species they harbor.

For now, the tiny gecko from Son La stands as both a scientific milestone and a warning, in the hidden crevices of limestone hills, life continues to evolve—but its future is far from secure. (Wage Erlangga)