China Records Its First-Ever Freshwater Cavesnail: Eyeless Erhaia dijiang Found in Yunnan Karst Cave

Key facts

• Researchers have documented Erhaia dijiang, a tiny, translucent, completely eyeless snail found in a limestone cave in Hongta District, Yuxi City, Yunnan Province, as the first freshwater cavesnail formally recorded from China.
• The new species belongs to the family Erhaiidae within the superfamily Truncatelloidea and was described in the journal Subterranean Biology.
• The discovery pushes the known upper elevation limit for cave-dwelling freshwater snails in Asia above 2000 meters, with the holotype shell (2.05 mm long, 0.98 mm wide) collected at 2062 meters.
• The snails were first collected in August 2025 using a fine net with mesh smaller than 1.5 millimeters; only three live individuals and one empty shell were found, and specimens were preserved in 95 percent ethanol and deposited at the Museum of Biology, Nanchang University.
• The species shows classic troglobitic traits: complete absence of eyes, loss of pigment, a thin slightly reflexed outer lip, no tooth on the columella, and photophobic behavior in laboratory aquaria.
• Molecular analysis of a 623-base-pair COI sequence (GenBank accession PZ310334) placed Erhaia dijiang as a sister group to Erhaia daliensis with an uncorrected p-distance of 10.2 percent.
• Prior to this finding, freshwater cavesnails of the family Erhaiidae had only been recorded in Japan, making the Yunnan discovery a significant expansion of the known range of subterranean freshwater gastropods in East Asia.