Freshwater snails » Shell shape » Shell taller than wide » Dextral shell » Family: Lymnaeidae (1) » Lymnaeidae with short spires (2) » Lymnaeidae with tall spires (3) » Lymnaeidae with tall spires (4) » Lymnaeidae with tall spires (5> » Radix balthica »
The shells of this family do not possess an operculum. Many empty freshwater snail shells may be found without an operculum. If your specimen does not have an operculum and does not match the shape and/or descriptions on the following pages, please go back and try the group with an operculum.
Radix balthica
(Linnaeus, 1758)
(The image bottom left illustrates
the mantle after the
shell has been removed)
Radix balthica (Linnaeus, 1758)
Description: The shell of this species is probably the most variable of all freshwater species. The typical shell may be described as thin and moderately glossy, with 4½ – 5 whorls, the last of which forms up to three-quarters of the total height of the shell. The mouth is large and exceeds the height of the spire which is pointed. The upper edge of the mouth aperture always meets the body of the shell at less than a right angle, even in those cases where the mouth flares out in a similar way as in R. auricularia. Umbilicus formed as a slight cleft.
Size: Height: 12 – 20 mm. Breadth: 7 – 13 mm.
Habitat: It is found in all freshwater habitat throughout Britain, sometimes on dry land. In those waters which dry up in summer, it buries itself in mud or under stones. A dwarf form is found in some brackish waters.
Confusion has been caused in the past not only by the variabilty of the shell characters, but by the complex synonymy of two closely related species. This is discussed by Falkner et al. (2001) and Falkner et al. (2002), and is summarized by Anderson (2005), leading to the change of name to Radix balthica.
Recent work by Schniebs et al. (2011) to find reliable distinguishing characters from other European Radix species has been published in Journal of Conchology and the abstract to the paper Intraspecific morphological and genetic variability in Radix balthica (Linnaeus 1758) (Gastropoda: Basommatophora: Lymnaeidae) with morphological comparison to other European Radix species is available by clicking on the text link.
References:
ANDERSON R. 2005 An annotated list of the non-marine mollusca of Britain and Ireland. Journal of Conchology 38: 607–637.
FALKNER G., BANK R.A., & VON PROSCHWITZ T. 2001 Checklist of the non-marine Molluscan Species-group taxa of the States of Northern, Atlantic and Central Europe (CLECOM 1) Heldia 4: 1–76.
FALKNER G., RIPKEN T.E.J. & FALKNER M. 2002. Mollusques continentaux de France Liste de Référence annotée et Bibliographie. Patrimoines Naturels, 52 Museum d'Histoire Naturelle, Paris. 350pp.
SCHNIEBS K., GLÖER P., VINARSKI M.V. & HUNDSDOERFER A.K. 2011 Intraspecific morphological and genetic variability in Radix balthica (Linnaeus 1758) (Gastropoda: Basommatophora: Lymnaeidae) with morphological comparison to other European Radix species. Journal of Conchology 40: 657–678.