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Limpet

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iLimpets
Image:Napfschnecken Galizien2005.jpg
Patella vulgata limpets in their natural habitat (here northwestern Galicia). One animal was separated from the rock and turned over for the photograph to have a view of the underside and muscular foot.
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Patellogastropoda
Lindberg, 1986
Suborders

See text.

Limpets are marine molluscs in the order Patellogastropoda with flattened, cone-shaped shells. They live throughout the intertidal zone, from the high zone (upper littoral) to the shallow subtidal on the rocky coasts of most oceans. Limpets can be commonly found attached to rocks, looking like little disks or bumps on the rock surface. They attach themselves to the substratum using pedal mucus and a muscular "foot", which enables them to remain attached through dangerous wave action and which also seals against the rock to protect from desiccation during low tide. Limpets forage by grazing on algae found on rock surfaces. They scrape films of algae from the rock with a radula, a ribbon-like tongue with rows of teeth. Limpets move by rippling the muscles of their foot in a wave-like motion.

Some limpets have a hole at the top, through which gaseous exchange can occur. Most limpets are less than 3 in (8 cm) long, but a West Mexican Limpet grows to be 8 ins (20 cm).

Contents

[edit] Homing behaviour

Some species of limpets return to the same spot on the rock known as a "home scar" just before the tide recedes.[citation needed] In such species, the shape of their shell often grows to precisely match the contours of the rock surrounding the scar. This behaviour presumably allows them to form a better seal to the rock and may help protect from either predation or desiccation. It is still unclear how limpets find their way back to the same spot each time, but it is thought that they follow a mucus trail left as they move. Other species, notably Lottia gigantia seem to "garden" a patch of algae around their home scar. They will aggressively push other organisms out of this patch by ramming with their shell, thereby allowing their patch of algae to grow for their own grazing.

[edit] Predators and threats

Limpets are preyed upon by a variety of organisms including shore-birds and humans. They can be long lived, with tagged specimens surviving for more than 10 years. If the limpet lives on bare rock then it grows at a slower rate but can live for up to 20 years.[citation needed]

Limpets found on sheltered shores (limpets that are less frequently in contact with wave action, and thus less frequently in contact with water) have a greater risk of desiccation due to the effects of sunlight, water evaporation and the wind. To avoid drying out they will clamp to the rock they inhabit, minimizing water-loss from the rim around their base. As this occurs chemicals are released that promote the vertical growth of the limpet's shell.

[edit] Taxonomy

[edit] References

de:Napfschnecke pt:Docoglossa

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