''Lottia gigantea'', common name the owl limpet, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of sea snail, a true limpet, a marine gastropod mollusc in the family

Lottiidae Lottiidae is a family of sea snails, specifically true limpets, marine gastropod mollusks in the superfamily Lottioidea and the clade Patellogastropoda (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). Subfamilies 200 ...

. Its genome has bee
sequenced
at the

Joint Genome Institute The U.S. Department of Energy (DOE) Joint Genome Institute (JGI), first located in Walnut Creek then Berkeley, California, was created in 1997 to unite the expertise and resources in genome mapping, DNA sequencing, technology development, and i ...

Distribution

The owl limpet is found on the Pacific coast of North America from northern California to southern Baja California.

Description

The owl limpet grows to a length of up to nine centimetres. The often much eroded

shell Shell may refer to: Architecture and design * Shell (structure), a thin structure ** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses ** Thin-shell structure Science Biology * Seashell, a hard o ...

has an elongated low cone shape with the

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex, ...

close to one end. The anterior slope is concave. The general colour is brownish grey with pale markings and the foot is pale grey with a yellow or orange sole. There is also a small form that lives on the shells of mussels. It is even more elongated, up to twenty-five millimetres long, and dark blue with concentric growth rings. ''Lottia gigantea'' present a muscular orange foot.Eogastropoda: Rocky Shore Limpets
/ref> Round the edge of the foot the owl limpet has a distinctive pallial

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

system which uses currents caused by the beating of cilia to circulate water over the gills when submerged.

Ecology

Habitat

It is most abundant in California and favours vertical rock faces in wave-swept areas in the upper

littoral zone The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal a ...

. It grows slowly and may live for up to twenty years. It browses on microalgae growing on rock surfaces. The owl limpet is a territorial species and some individuals return to the same specific homesite every time the tide goes out. The limpet's contours grow to fit the homesite rock surface tightly.

Life cycle

Owl limpets are

protandric hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have sepa ...

s. They spend about two years as juveniles before starting their reproductive lives as male limpets. If they survive long enough, some of them later transform into females.

Spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: ...

ing takes place once a year in the winter. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

e are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

and form part of the

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. They may be transported large distances by currents before settling on suitable rock surfaces.Natural History Museum
/ref> Larger individuals will themselves have encrusting animals such as barnacles and algae growing on their shells. Sometimes the shell will be used by other limpets or chitons for grazing on the microalgae that grows there. The black oystercatcher, ''Haematopus bachmani'' is the only known

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

of the owl limpet but they are also harvested by humans for food.

Feeding habits

Large female limpets graze on the film of algae growing on rocks and defend their territory against other owl limpets, mobile gastropods, mussels, sea anemones, barnacles and

macroalgae Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such as ...

. Large competitors are dislodged by pushing them away with the anterior part of the shell, and if barnacles settle, they are rasped away with the radula. In this way, each individual maintains a territory of about 900 square centimetres. It selectively grazes its algal meadow maintaining a turf depth of at least one millimetre. In spring and summer, these green meadows are visible from fifteen metres away and if the owl limpet is transplanted to a new area, it establishes a new meadow over the course of about three weeks.Wright W. G. (1982). "Ritualized behavior in a territorial limpet". ''

Journal of Experimental Marine Biology and Ecology The ''Journal of Experimental Marine Biology and Ecology'' is a peer-reviewed bimonthly journal which publishes work on the biochemistry, physiology, behaviour, and genetics of marine plants and animals in relation to their ecology. According to th ...

'' 60: 245-251.

References

External links

''Lottia gigantea'': Natural History Museum

* {{Taxonbar, from=Q3166907 Lottiidae Gastropods described in 1834 Taxa named by George Brettingham Sowerby I