Lottia gigantea Sowerby, 1834 

Common name(s): Owl limpet, giant owl limpet, solitary giant owl limpet

Phylum Mollusca
 Class Gastropoda
   Subclass Prosobranchia
   Order Patellogastropoda
    Suborder Nacellina
     Family Lottiidae
(Lottia gigantea at Dana Point, CA worn and overgrown with barnacles)
(Photo by: Dave Cowles May 1999)
Description:  Often a very large limpet (to 9 or 10 cm long).  Apex very near the front margin of the shell (near the first one-eighth), and decidedly lower than the highest part of the shell, which is posterior to it.  The apical blotch inside this shell appears somewhat like an owl, the muscle scar is often bluish, and the interior margin of the orifice has a brown band.  The exterior of the shell is almost always badly eroded, and is usually a light brown with whitish spots.  Has some radial ribs (often worn), and the margin is alightly scalloped.

How to Distinguish from Similar Species:  This limpet can grow much larger than other species on our coast.  It is the only one (especially the only large one) with the apex so far anterior and lower than the highest part of the shell.

Geographical Range:  Neah Bay, WA to Bahia de Tortuga, Baja California.  Scarce north of San Francisco; a few found on Oregon and Washington coasts.

Depth Range:  High to middle intertidal

Habitat:  Rocky intertidal, on bare rocks, common on cliffs and large boulders.  Solitary

Biology/Natural History:  Probably breeds in fall and early winter.  Large specimens 10-15 years old.  This limpet is unusual not only because it is so large, but because it has mantle folds on the lower surface of the mantle (pallial gills).  Pumps water over gills by cilia, left to right.  Territorial.  Some individuals are "homing", returning repeatedly to the same scar that exactly fit the margin of its shell.  Territories are usually about 1000 square centimeters.  Dislodge other limpets and small barnacles from their territory (the rock around them is usually seen to be bare except for microalgae which it grazes on but allows to grow--often in a distinctive patch).  Radular teeth are hardened with the iron-containing compound geothite and have silica on their base plates.  The rough limpet Colisella scabra may live on Lottia's shell.

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Dichotomous Keys:

Kozloff 1987, 1996
Smith and Carlton, 1975

General References:
Kozloff, 1993
Morris et al., 1980
Niesen, 1994

Scientific Articles:

General Notes and Observations:  Locations, abundances, unusual behaviors:

This specimen is at Little Corona del Mar, Ca.  Photo by Dave Cowles, March 2005.  Note the Balanus glandula barnacle nearby and the tar-spot algae.  This indivudual is likely keeping
the rock area below it bare by grazing.

A large individual at Dana Point, CA.  Photo by Dave Cowles, March 2005.  Note the convex upper surface and the apex near the very front (right).

Authors and Editors of Page:
Dave Cowles (2004):  Created original page