Researchers explore Shuanghe Cave in Guizhou province.[Photo provided to China Daily]

Shuanghe Cave in Guizhou province - which was named the longest cave in Asia on Saturday - houses a trove of wonders, including a lizardlike endangered species, 10 centimeters long, and fossils of vertebrates such as giant pandas and what appear to be rhinoceros, saber-tooth tiger and elephant remains.

The slithery lizard, which was found in an underground river in a major branch of the cave, appears similar to a giant salamander. A full definition of the new species will require further research by scientists.

Unlike scientific surveys on the surface, a cave can retain traces of a place for a long time, including its ancient geology, meteorology, paleontology and even hydrology, said Li Po, chief engineer of the Guizhou Academy of Sciences' Mountain Resource Research Institute.

"Those key elements will help us better understand the ancient environment and our current environment," he said. "Guizhou is truly rich in geological resources and many caves have unique ecosystems that need further research."

Shuanghe Cave is a karst formation that was discovered in the late 1980s. Nineteen major surveys have been carried out by Chinese and foreign researchers. This year's survey is currently underway.

The cave, located in Suiyang county, is the sixth-longest in the world, researchers said.

"The length of a cave system equals the total length of all its main caves, branch tunnels, cenotes and underground rivers," said Qian Zhi, secretary-general of Guizhou Cave Association.

A team of Chinese and French speleologists announced at a Saturday news conference that the surveyed passageways in Shuanghe Cave had reached 238.48 kilometers, making it the longest in Asia. Previously, the longest known Asian cave was the Clearwater Cave in Malaysia, with a length of 222 km.

The known longest cave system in the world is Mammoth Cave in central Kentucky, United States, with 663 km of surveyed passageways.

The cave researchers conducted a joint expedition on March 11 at Shuanghe Cave, attracting more than 30 experts from China, France, Canada and Portugal.

Jean Bottazzi, a well-known French caver who had lived in China for several years to explore the country's underground kingdom, found a new tunnel in Shuanghe Cave connecting with Duiwo Cave, where the new lizardlike species was found.

Duiwo Cave was discovered in 2003 but wasn't explored until 2015 because of technical difficulties. It has been measured at 8 km long so far after three years of exploration.