Marisa cornuarietis

Family

Ampullariidae

Species

Marisa cornuarietis (Linnaeus, 1758)

Common name

Giant ramshorn snail, apple snail

Description

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 on average measures 50 mm wide, with 3.5-4 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 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 adults generally appears flattened, as the apexApex:
The tip of the spire of a shell.
does not extend above the 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 juveniles' 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.
, on the other hand, have a more globoseGlobose:
Shell shape: to be roughly spherical or globular in shape.
shape and the apexApex:
The tip of the spire of a shell.
is well above the 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.
often appears to be bicolored with different color patterns on the dorsal and ventral surfaces. They almost always have 3-6 dark colored stripes; however, an unusual morph exists that is completely yellow. The body of this snail is yellow to grey with black blotches covering the entire body. The rigid structure that is used to block the opening of 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.
(operculum) is very small and can be retracted entirely into 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.
.

Native range

Southern and Central America

Distribution

North America:

• U.S.: Alabama, Alaska, Arizona, California, Florida, Georgia, Idaho, Texas

South America

Pacific Islands: Hawaii

Caribbean

Ecology

This omnivorous snail can be found in standing or slow-moving water. The adults lay their orange-colored eggs, measuring 2-3 mm, below the surface of the water. The eggs are often deposited on vegetation in a gelatinous matrix. Clutch size average 210 eggs with an incubation period of approximately 8-24 days. The snail is not hermaphroditicHermaphroditic:
State of having both male and female reproductive organs. (See also Hermaphrodite)
(both sexes exist). There has been evidence of sexual dimorphism, where the males have a more rounded apertureAperture:
The major opening of a shell that the body of the animal may be retracted.
(mouth) and a thicker 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.
, while the females have an oval-shaped apertureAperture:
The major opening of a shell that the body of the animal may be retracted.
(mouth) and thinner shells. This snail is of concern because of its ability to completely decimate the vegetation in its habitat. They also are capable of outcompeting native species through direct competition and predation on their eggs and young.

References

Barker 2002; Rawlings et al. 2007