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Terrestrial
Gastropods of the Columbia Basin, British Columbia
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| Key to Terrestrial Gastropods
of British Columbia
The following is an identification key to all terrestrial gastropods known from British Columbia. The species and their relative systematic position are given in the Systematic Checklist. The key relies on shell characters, if present, and external characters of the body, and keys out directly to species. A key to families and other higher categories of snails and slugs based solely on external features of the shell or animal is impractical, given that the classification of the pulmonate gastropods is based upon anatomy of the animals. This key is for adult snails and slugs. Adults of many species of snails can be recognised by a thickened or reflected lip, a downward turning of the last whorl at the outer lip, or by the development of teeth around the aperture. In others, where these features do not occur at maturity, recognition of adult specimens may be more difficult. Ideally several specimens should be studied. Notes on the body colour of the living animal are sometimes helpful. Weathered or eroded shells may not show surface sculpture or colouration well, and may prove difficult to key out. Consult fresh specimens whenever possible. Many species of slugs are difficult or impossible to distinguish by external characters, as are members of the family Succineidae. Reference to internal anatomy is therefore unavoidable in identifying these gastropods. As a result, slugs and succineid snails are not fully keyed out, and some anatomical distinctions are presented in the text only for these groups. The snails of the genus Vertigo and Nearctula are not keyed out to species. Significant characteristics of those species recorded from the Columbia Basin region are presented in a table preceding the species descriptions. For completeness and as an aid to the beginner who may on occasion find certain aquatic and semi-marine snails living in close association with terrestrial molluscs, several species are included here that are not truly terrestrial. These are not included in the text and are marked either as "semi-marine" or "freshwater". Finally, those gastropods known from the Kootenay
region of British Columbia are set in bold type and are linked
to the main text.
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Copyright © Royal
BC Museum |
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