A team from the National and Kapodistrian University of Athens has identified a completely new genus and species of subterranean freshwater snail in the Peloponnese region of southern Greece. The animal, named Cyllena hermes, is a small, unpigmented, eyeless aquatic snail fully adapted to life underground.
The discovery was made in a highly restricted area within a single karstic spring near Mount Kyllini at roughly 610 meters elevation, where groundwater emerges from carbonate bedrock and forms a small stream. That stream flows toward Lake Stymphalia, connecting to the broader underground hydrological network of the Stymphalia closed karst basin. Such systems act as isolated aquatic caves, where species evolve under stable yet fragile conditions and dispersal is extremely limited.
Cyllena hermes is currently known from only this one locality, meaning its survival depends entirely on the persistence of the local water source. Even minor changes in groundwater availability can reshape habitat conditions, affecting flow rate, water chemistry, and overall ecosystem stability. The researchers classified the species as Vulnerable under IUCN Red List criteria, reflecting its susceptibility to drought and water extraction in neighboring areas.
The naming draws on ancient Greek mythology linked to the mountain where the snail lives. The genus name Cyllena honors Cyllene, the nymph who raised Hermes on Mount Kyllini, while the species epithet hermes pays tribute to Hermes, the messenger god said to have been born in a cave on that same mountain. Taxonomically, the team created a monotypic genus — a genus represented by only this single species — highlighting both its uniqueness and the narrow evolutionary context in which it was found.
Knowledge takeaway: A single karst spring in Greece hosts a newly discovered genus of blind, pigmentless snail that exists nowhere else on Earth, highlighting how vulnerable underground freshwater ecosystems are to climate variability and human water use.