Lymnaeidae

Family

Lymnaeidae

Species

Radix auricularia (Linnaeus, 1758)

R. peregra (Muller, 1774)

Lymnaea stagnalis (Linnaeus, 1758)

Common name

Radix auricularia: Big-ear Radix, Ear pond snail

R. peregra: Wandering pond snail

Lymnaea stagnalis: The great pond snail, Stagnant pond snail, Swamp lymnaea

Description

The shells of this freshwater-dwelling group are not patterned and they do not posses an operculumOperculum:
A rigid structure that blocks the opening/aperture of the shell (partially/wholly) when the body of the snail is retracted. This structure is often attached dorsal to the tail of the animal. It can be chitinous, proteinaceous or calcareous. Often observed in aquatic species. (See also epiphragm).
. They will attain a maximum heightHeight:
The height of the shell is a measure of the distance between the apex and the most basal part of the shell OR the measurement taken from the apex of the shell to the base, when measured parallel to the axis of the shell.
of 70 mm. The tentaclesTentacles:
Sensory projections on the head end of a mollusc. There are generally two pairs; upper (posterior) and smaller, lower (anterior). The upper pair bears the eyes. In many snails the eyes are located at the tips of this structure; however, in Basommatophoran snail species, the eyes are located at the base of the tentacles.
of these species are characteristically triangular in shape with the small eyes located at the baseBase:
This is the lower or underside of the shell; opposite of apical.
.

Radix auricularia: The big-ear Radix may be as large as 14-30 mm high and 12-25 mm wide, with 4-5 whorlsWhorls:
Pleural of whorl. A whorl is a complete spiral turn/growth of the shell of a mollusc. The whorls are counted from the apex outwards.
. The whorlsWhorls:
Pleural of whorl. A whorl is a complete spiral turn/growth of the shell of a mollusc. The whorls are counted from the apex outwards.
of this species rapidly increase towards the very large body whorlBody whorl:
The large, final coil (most recently formed) of a mollusc shell that contains the body of the snail, i.e. from the aperture to approximately one whorl back.
. The shellShell:
A hard, inflexible, calcareous or chitinous structure that vary in size and may either completely encasing the animal, covering some part of it or be internal.
is slightly glossy and smooth. The thin shellShell:
A hard, inflexible, calcareous or chitinous structure that vary in size and may either completely encasing the animal, covering some part of it or be internal.
of this species is generally tan to pale yellow. The apertureAperture:
The major opening of a shell that the body of the animal may be retracted.
is ear-shaped and the umbilicusUmbilicus:
A navel-like indentation or depression in the center of the shell. It may be described as open (inside of columella visible), partially closed (partly covered by base of aperture) or completely closed (not visible). The width of the umbilicus is a measure of its greatest diameter.
(navel) may be slightly open or closed altogether. The body of the animal may have small white spots on the headHead:
The area of a mollusc's body that has the tentacles, eyes and mouth.
and tentaclesTentacles:
Sensory projections on the head end of a mollusc. There are generally two pairs; upper (posterior) and smaller, lower (anterior). The upper pair bears the eyes. In many snails the eyes are located at the tips of this structure; however, in Basommatophoran snail species, the eyes are located at the base of the tentacles.
.

R. peregra: The wandering snail is between 18-20 mm high and 12-13 mm wide. The shellShell:
A hard, inflexible, calcareous or chitinous structure that vary in size and may either completely encasing the animal, covering some part of it or be internal.
of this species is tan to brown and may possess a blackish cover. The body of the animal is greenish with black and dirty-yellow spots covering it.

Lymnaea stagnalis: This species is very large when compared to the other 2 species in this group. It can attain a heightHeight:
The height of the shell is a measure of the distance between the apex and the most basal part of the shell OR the measurement taken from the apex of the shell to the base, when measured parallel to the axis of the shell.
of 45-70 mm and a widthWidth:
The width of the shell is the maximum distance across the shell (including the aperture).
of 20-34 mm. The shellShell:
A hard, inflexible, calcareous or chitinous structure that vary in size and may either completely encasing the animal, covering some part of it or be internal.
is also tan colored and does not have any obvious markings.

Distribution

Radix auricularia

North America:

• U.S.: Massachusetts, New Jersey, New York, Nevada, Pennsylvania, Vermont

Europe: Croatia, Czech Republic, Germany, British Isles, Netherlands, Poland, Slovakia, Ireland (and possibly other countries)

Asia

R. peregra

North America:

• U.S.: Massachusetts, New Jersey, New York, Pennsylvania, Vermont

Europe: Croatia, Czech Republic, Germany, British Isles, Netherlands, Poland, Slovakia, Ireland (and possibly other countries)

Asia

Lymnaea stagnalis

North America:

• U.S.: Illinois, Massachusetts, Michigan, New Jersey, New York, Pennsylvania, Vermont, Wisconsin,

Europe: Croatia, Czech Republic, Germany, British Isles, Netherlands, Poland, Slovakia, Ireland (and possibly other countries)

Asia

Ecology

The species in this group prefers stagnant or very slow moving water with dense vegetation. R. auricularia is an intermediate host for a human pharyngeal parasite (Clinostomum complanatum).

Synonyms

Radix auricularia:

• Helix auricularia Linnaeus, 1758
• Limnaea auricularia
• Lymnaea auricularia (Linnaeus, 1758)
• Radix auriculatus Montfort, 1810

R. peregra:

• Buccinum peregrum Muller, 1774
• Radix labiata (Rossmassler, 1835)
• Lymnaea peregra (Muller, 1774)
• Lymnaea pereger

Lymnaea stagnalis:

• Helix stagnalis Linnaeus, 1758
• Limnaea vulgaris Locard, 1840
• Limnaea turgida Locard, 1882
• Lymnaea stagnalis var. ssorensiana W. Dybowski, 1912
• Lymnaea stagnalis var. subulata angarensis B. Dybowski, 1912

References

Anderson 2005; Chung et al. 1998; Kantor et al. 2009