Key to Terrestrial Gastropods of
British Columbia
- 1a
- Sluglike gastropods: shell absent or much reduced;
shell not in definite coils and internal or small and partially
external on the posterior part of the mantle - 69
- 1b
- Snail-like gastropods: shell coiled into
which the animal can more or less retract - 2
- 2a
- Shell height greater than width - 3
- 2b
- Shell width greater than or equal to height - 17
- 3a
- Aperture with 1 or more denticles - 4
- 3b
- Aperture without denticles - 9
- 4a
- Adults typically with 4 or more denticles within
the aperture - 8
- 4b
- Adults with 1 or 2 denticles - 5
- 5a
- Aperture greater than ½ shell height; usually
associated with marine marshes - Myosotella
myosotis - semi-marine
- 5b
- Aperture less than ½ shell height;
fully terrestrial - 6
- 6a
- Shell white; spire gradually tapering - Carychium
occidentale
- 6b
- Shell brownish; spire bluntly pointed - 7
- 7a
- Adults with a single denticle on the parietal
wall, connected to the top of the outer lip and sometimes a columellar
denticle (obscured by the columellar lip); juveniles with apertural
dentition; no crest - Lauria cylindracea
Introduced to British Columbia (Forsyth in press)
- 7b
- Adults usually only with a columellar denticle
(obscured by the columellar lip); rarely with a small parietal
denticle, but not connected to the top of the outer lip; juveniles
without apertural denticles; crest hardly or only moderately developed
- Pupilla hebes
- 8a
- Shell whitish or translucent horn-coloured (denticles
at least 5) - Gastrocopta pentodon
- 8b
- Shell brown, reddish brown or yellowish
brown (if yellowish, then with only 4 denticles) - Vertigo
species
A key to Vertigo and Nearctula species is not given
the amount of variation exhibited in some species. Four Vertigo
are known from the Kootenay region: V.
elatior, V. gouldii,
V. modesta and V.
ovata.
- 9a
- Shell with well-spaced lamellar axial ribs —Zoogenetes
harpa (Figure)
- 9b
- Shell smoothish or with axial striae only
- 10
- 10a
- Shell more or less cylindrical - 11
- 10b
- Shell not cylindrical - 15
- 11a
- Early whorls of the spire lost in adults; operculum
present; associated with marine marshes — Cecina
manchurica — semi-marine
- 11b
- Early whorls of the spire not lost; no operculum;
fully terrestrial — 12
- 12a
- Shell surface very smooth with a high gloss; umbilicus
absent; lip with a narrow riblike thickening within — Cionella
lubrica (Figure)
- 12b
- Shell surface not glossy or only somewhat
glossy; umbilicus present; lip without a riblike thickening within
- 13
- 13a
- Outer lip narrowly reflected and slightly thickened;
columella with a small denticle obscured by the columella except
when viewed from a slight angle — Pupilla hebes
- 13b
- Outer lip neither reflected nor thickened;
no columellar denticle - 14
- 14a
- Shell tapered-cylindrical; axial striae fine;
length 1.8-2.5 mm (5½-6½ whorls) - Columella
edentula (Figure)
- 14b
- Shell very cylindrical; axial striae rather
coarse; length 2.5-3.0 mm (6-7 whorls) - Columella
columella (Figure)
- 15a
- Whorls about 3; columella never strongly twisted
or thickened; eyes at the tips of ocular tentacles. — Succinea
species, Oxyloma species, Catinella species
(Figure)
Identification of species (and to a lesser extent, identification
of genera) by shell characters is unreliable
- 15b
- Whorls 4-6; columella often strongly twisted
or thickened; no ocular tentacles (eyes at the base of sensory
tentacles) - 16
- 16a
- Operculum present; associated with marine marshes
- Assiminea californica — semi-marine
- 16b
- Operculum absent; living in, or amphibious
near, freshwater - Lymnaeidae — freshwater
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