More new geckos have been found hidden in Southeast Asian limestone towers

Landscapes in Southeast Asia once thought that they encompassed biological evolution instead could stay its fires.

Karst ecosystems are referred to as arks of biodiversity, a term that highlights their biological wealth, but also implies that they simply preserve ancient lines. These landscapes, with their isolated caves, rocks and sycolates, were thought to accommodate species from extinction without much contribution to evolution.

But the discovery over the last few years of nearly 200 gecko species in such regions reveals that karsts are far from standing. “They are not museums, but specific centers,” says evolutionary biologist Lee Grismer from La Sierra University in Riverside, Calif.

When Grismer first researched Myanmar’s karst landscapes in 2017, the wealth of hidden life inside the limestone towers and caves left him surprised. During a 19-day expedition, these ancient rock formations, suddenly rising from the surrounding agricultural land, discovered geckos so distinct and unexpected that his team identified 12 new species.

Since then, Grismer and his colleagues have entered similar formations throughout Southeast Asia, entering the evolutionary secrets they have. At the beginning of 2024, an expedition to the western Cambodia discovered three new species of bent gecko and a thin-all gecko-all detail in future letters-bringing the number of gecko species he described about 185 .

Gecko discoveries highlight this dynamism. Many geckos that reside in karst belong CyrtodactylusThe third largest vertebral gender in the world with nearly 400 species described so far. Geckos of this genus discovered by Grismer and his team are among the most recently evolved members of their groups. They exhibit unique adaptations, such as elongated limbs, larger eyes, and more pleasant heads, enabling them to climb the faces of clean rock, just like expert climbers.

Grismer compares karst formations on the islands in an archipelago. Eachdo formation, he says, serves as an evolutionary microcosm, producing completely distinct species from neighboring karsts. “Species come from completely different species groups and different periods throughout history.”

The real extent of gecko’s diversity in karst remains unknown. Grismer and his colleagues surveyed only about 20 percent of the formations in Western Cambodia, and he plans to return there and in Myanmar in 2025. “It would not surprise me if there are 200 species there.”