Lottia gigantea
Encyclopedia
Lottia gigantea, common name
the owl limpet, giant owl limpet or solitary giant owl limpet, is a species
of sea snail
, a true limpet
, a marine
gastropod
mollusc
in the family Lottiidae
. Its genome has been sequenced at the Joint Genome Institute
.
.
has an elongated low cone shape with the 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. Its foot and head are entirely black.
Round the edge of the foot the owl limpet has a distinctive pallial
gill
system which uses currents caused by the beating of cilia to circulate water over the gills when submerged.
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 rock surface tightly.
ing takes place once a year in the winter. The larva
e are pelagic
and form part of the zooplankton
. They may be transported large distances by currents before settling on suitable rock surfaces.
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
of the owl limpet but they are also harvested by humans for food.
.
Large female limpets graze on the film of algae growing on rocks and defend their territory against other owl limpets, mobile gastropods, mussel
s, sea anemone
s, barnacle
s and macroalgae
. 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.
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
the owl limpet, giant owl limpet or solitary giant owl limpet, is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, a true limpet
Limpet
Limpet is a common name for a number of different kinds of saltwater and freshwater snails ; it is applied to those snails that have a simple shell which is more or less conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snails.The name limpet is most...
, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod
Gastropoda
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...
mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
in the family Lottiidae
Lottiidae
Lottiidae is a family of sea snails, specifically true limpets, marine gastropod mollusks in the superfamily Lottioidea and the clade Patellogastropoda .- 2005 taxonomy :...
. Its genome has been sequenced at the Joint Genome Institute
Joint Genome Institute
The U.S. Department of Energy Joint Genome Institute was created in 1997 to unite the expertise and resources in genome mapping, DNA sequencing, technology development, and information sciences pioneered at the DOE genome centers at Lawrence Berkeley National Laboratory , Lawrence Livermore...
.
Distribution
The owl limpet is found on the Pacific coast of North America from Washington state to Baja CaliforniaBaja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
.
Description
The owl limpet grows to a length of up to nine centimetres. The often much eroded shellGastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
has an elongated low cone shape with the apex
Apex (mollusc)
Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...
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. Its foot and head are entirely black.
Round the edge of the foot the owl limpet has a distinctive pallial
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...
gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
system which uses currents caused by the beating of cilia to circulate water over the gills when submerged.
Habitat
It is most abundant in California and favours vertical rock faces in wave-swept areas in the upper littoral zone. 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 rock surface tightly.
Life cycle
Owl limpets are protandric hermaphrodites. 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. SpawnSpawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
ing takes place once a year in the winter. The larva
Larva
A larva 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
Pelagic zone
Any water in a sea or lake that is not close to the bottom or near to the shore can be said to be in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means "open sea". The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes...
and form part of the zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
. They may be transported large distances by currents before settling on suitable rock surfaces.
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
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
of the owl limpet but they are also harvested by humans for food.
Feeding habits
Juveniles and small males often graze on the shells of the mussel, Mytilus californianusCalifornia mussel
The California mussel, Mytilus californianus, is a large edible mussel, a marine bivalve mollusk in the family Mytilidae.This species is native to the west coast of North America, occurring from northern Mexico to the Aleutian Islands of Alaska...
.
Large female limpets graze on the film of algae growing on rocks and defend their territory against other owl limpets, mobile gastropods, mussel
Mussel
The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...
s, sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
s, barnacle
Barnacle
A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have...
s and macroalgae
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
. 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
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...
. 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.
Further reading
- Denny M. W. & Blanchette C. A. (2000). "Hydrodynamics, shell shape, behavior and survivorship in the owl limpet Lottia gigantea". Journal of Experimental BiologyJournal of Experimental BiologyThe Journal of Experimental Biology is a peer-reviewed scientific journal in the field of comparative physiology and integrative biology. It is published by The Company of Biologists from editorial offices in Cambridge, United Kingdom.- History :...
203(17): 2623-2639. abstract, PDF - Fisher W. K. (1904). "The anatomy of Lottia gigantea Gray". Zoologische Jahrbücher. Abteilung für Anatomie und Ontogenie der Tiere 20: 1-66.