Spiralix cf. Spiralix rayi (Bourguignat, 1883)

Stygobiont. Known distribution: karstic aquifers in the Côte-d’Or, Nièvre, Haute-Marne and Yonne. Basionym: Lartetia rayi. Probable synonym: kuiperi Boeters & Falkner, 2009.
 
« Shell with a regular conoid shape, attenuated at the apex. Test thin, shiny, smooth, diaphanous. Spire composed of six whorls with regular growth, separated by a very deep suture; whorls with a well-rounded profile; apex very obtuse, smooth, shiny. Umbilicus reduced to a simple, small and narrow umbilical slit. Aperture patulescent especially at the base, almost round, its major axis roughly parallel with the general axis of the shell. Peristome continuous, slightly flared; external edge arched forward, and leaving towards the insertion a pleurotomoidal notch, wide and fairly deep; lower edge projected forward; columellar edge slightly reflected on the umbilicus. » – A. Locard: “Contributions à la faune malacologique francaise. III. Monographie du genre Lartetia”, Annales de la Société Linnéenne de Lyon n. s. tome 29, Lyon 1883, page 207.

Above: a slightly subadult specimen collected in sediments, Fontaine d’Ouche, ruisseau de Larrey, Dijon, Côte-d’Or, Yonne drainage basin. Altitude ≈ 245m. 2,2mm.
A large adult from the same spring. 2,6mm.
Shape variations. Same spot. 2,7-2,4-2,5mm.
All the specimens bear a conspicuous labial thickening.
 
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