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| Cyllena hermes Radea & Protopapas, in Radea, Protopapas, Parmakelis et Koskeridou, 2026. |
Abstract
A new stygobiont hydrobiid genus and species is described from the Stymphalia karst basin (Peloponnese, Greece). Cyllena hermes gen. et sp. nov. is distinguished from other valvatiform or valvatiform–planorboid stygobiont hydrobiids by a unique combination of shell and anatomical characters, supporting the establishment of a new monotypic genus. It is currently known from a single karstic spring connected to the subterranean hydrological network of the Stymphalia polje, indicating a highly localized distribution. Following a precautionary approach, and in accordance with IUCN criteria, the species is here considered to qualify as Vulnerable (VU D2). The discovery of the new genus contributes to the documentation of subterranean aquatic gastropod diversity in Greece and emphasizes the need for further targeted exploration of karst ecosystems in the region.
Keywords: Endemism, Hydrobiidae, IUCN, Peloponnese, karst aquifer
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| Cyllena hermes gen. et sp. nov. Shell views of collected specimens. A, G, J, M, P dorsal views B, H, K, N, Q ventral views C–E, I, L, O, R lateral views F operculum A–E holotype. Scale bar: 1 mm. |
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| Cyllena hermes gen. et sp. nov. Views from a single immature specimen. A dorsal view B ventral view C, D lateral view E–G scanning electron micrographs of shell and protoconch respectively. Scale bars: 1 mm (A–E); 100 μm (F); 50 μm (G). |
Systematic description
Class Gastropoda Cuvier, 1795
Subclass Caenogastropoda Cox in Moore, 1960
Order Littorinimorpha Golikov & Starobogatov, 1975
Superfamily Truncatelloidea J.E. Gray, 1840
Family Hydrobiidae W. Stimpson, 1865
Cyllena Radea & Protopapas, 2026, gen. nov.
Type species. Cyllena hermes sp. nov. by original designation.
Diagnosis. Shell minute, valvatiform to planorboid; umbilicus wide, with earlier whorls visible; soft body unpigmented; eyes absent; bursa copulatrix pyriform; a single seminal receptacle [proximal, rs2 (Radoman 1973)] large and irregular in shape; penis large, dorso-ventrally flattened, distally blunt with papilla and proximally folded, bearing a single, elongate, blunt, medial lobe.
Etymology. The generic name derives from the Greek mythology: Cyllena (Κυλλήνη in Greek) was a nymph of Mt Kyllini, Korinthia, Peloponnese, and the nurturer of the god Hermes. Gender feminine.
Cyllena hermes Radea & Protopapas, 2026, sp. nov.
Etymology. The specific name, used in apposition, is derived from Greek mythology. Hermes (Ἑρμῆς in Greek) was one of the twelve Olympian gods, the messenger of the other Olympian deities, and was born in a cave on Mt Kyllini.
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| Live specimens of Cyllena hermes gen. et sp. nov. A–F live mature specimen, shown from the moment of emergence from the shell to active locomotion while foraging G–I another mature specimen; White arrows indicate the direction of movement J immature specimen floating at the water surface while feeding K caddisfly case (Insecta, Trichoptera) constructed from gastropod shells, including shells of Cyllena hermes gen. et sp. nov. Scale bars: 1 mm. |
Canella Radea, Dimitrios Protopapas, Aristeidis Parmakelis and Efterpi Koskeridou. 2026. From the Dark to the Light: A New Genus and Species of stygobiont hydrobiid (Caenogastropoda, Truncatelloidea) from southern Greece. Subterranean Biology. 57: 1-21. DOI: doi.org/10.3897/subtbiol.57.189090 [18 Jun 2026]
