Scientists in southwestern China discovered Erhaia dijiang, the country’s first known freshwater cave snail. Documented in Subterranean Biology by He et al., the eyeless and translucent troglobiont lives 2,062 meters above sea level in a Yunnan Province karst cave, where field surveys in August 2025 located only three living adults.
Discovery of Erhaia dijiang in Yunnan Province
Deep inside a mountain cave in the Hongta District of Yuxi City, Yunnan Province, researchers have documented China’s first known freshwater cave snail. According to Scitechdaily, the newly identified species has been formally described as Erhaia dijiang in the journal Subterranean Biology
by Yue-Ming He, Hong-Quan Xiang, Jin-Mei Yang, Hui Zheng, Suo-Zhu Yang, Yu-Feng Zhou, and Jian Zheng.
The finding addresses a notable gap in scientific exploration concerning East Asia’s underground freshwater ecosystems. While surface habitats receive extensive study, underground water systems remain far less explored. The tiny freshwater snail features no eyes, almost no color, and a translucent shell that reveals its delicate body underneath. These biological traits classify Erhaia dijiang as a troglobiont, an organism entirely specialized for permanent darkness where vision and protective coloring provide no evolutionary advantage.
High-Altitude Karst Habitat and Laboratory Behavior
The cave lies 2,062 meters, or 6,765 feet, above sea level. According to Scitechdaily reporting on the study published on May 29, 2026, this represents the highest elevation ever recorded for a cave-dwelling member of the family Erhaiidae. The discovery demonstrates that freshwater cave snails can survive in high-altitude karst systems exceeding 2,000 meters.
Karst landscapes develop when water slowly dissolves soluble rock, forging networks of caves, underground streams, and isolated pools that function similarly to biological islands. Within this environment, Erhaia dijiang inhabits shallow cave water less than one meter, or 3.3 feet, deep, living among gravel and broken stone. The water maintains a relatively stable temperature close to 20°C, or 68°F. The snails graze on diatoms spread across submerged rocks and consume fish food under laboratory conditions.
Researchers connected the snail’s appearance to its name, which draws inspiration from Di Jiang,
a mountain god depicted in the ancient Chinese text Classic of Mountains and Seas
as a faceless creature. Laboratory observations showed that the snails strongly avoided light, crawling into narrow spaces beneath rocks whenever exposed to illumination.
Population Vulnerability and Conservation Concerns
Heavy rain occasionally forces fast water through the cave, washing a small number of snails toward the outlet. However, researchers found no individuals in nearby surface streams. The animals remained inside the cave and within two meters, or 6.6 feet, of the entrance, indicating that brief exposure to the external environment is unsuitable for them.
This extreme specialization leaves the species highly vulnerable. During a survey conducted in August 2025, scientists located only three living adults and a single empty shell. Because they observed no juveniles, researchers raised serious concerns regarding whether the population is reproducing successfully, describing its survival outlook as far from optimistic.
The extremely restricted habitat and low observation count leave the species defenseless against local threats such as pollution, cave disturbance, or alterations in water flow. Consequently, the researchers urged for wider surveys across China’s caves to discover whether the species exists elsewhere and to find other overlooked organisms. They also advised that conservation measures be developed quickly, noting that damage to a single underground habitat can threaten an entire species confined to it.
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