Bythiospeum alpinum
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| Bythiospeum alpinum | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Subclass: | Caenogastropoda |
| Order: | Littorinimorpha |
| Family: | Moitessieriidae |
| Genus: | Bythiospeum |
| Species: | B. alpinum |
| Binomial name | |
| Bythiospeum alpinum Bernasconi, 1988 | |
Bythiospeum alpinum is a species of very small freshwater snail that has an operculum, an aquatic gastropod mollusk in the family Moitessieriidae.[2] It is only known from two locations in central Switzerland, where it is endemic. It is listed under Swiss law.[1] This minute groundwater snail has a translucent, elongated shell averaging 2.8 mm in length and is distinguished from other European Bythiospeum species by its distinctive female reproductive anatomy, specifically the unusually positioned female reproductive pouch. As a specialized stygobiont, B. alpinum spends its entire life cycle submerged in the cold, oxygen-rich groundwater of karst aquifers, making it particularly vulnerable to changes in water quality and flow patterns.
Bythiospeum alpinum is a minute groundwater snail with an elongated, almost conical shell that averages 2.8 mm long and 1.3 mm wide (length-to-width ratio approximately 2.2). The thin, glassy shell bears about five gently convex whorls; the last whorl occupies roughly half the total height, and the narrow umbilical slit is barely visible. The oval aperture measures close to 1.0 × 0.7 mm, and the horny operculum is discoid and tightly coiled, its length a little under one quarter of the shell's. Internally, the species is set apart from all other European Bythiospeum by a distinctive female reproductive pouch (bursa copulatrix) that is long, folded and attached off-centre—rather than at the tip—of the duct leading to the oviduct. Males possess a simple, cone-shaped penis that rarely shows lobes. The radula follows the typical hydrobioid 1–(10–12)–1 tooth formula.[3]