Lottia scabra
Encyclopedia
Lottia scabra or the rough limpet is a species
of sea snail
, a true limpet, a marine gastropod mollusk in the family
Lottiidae
. It is found on the Pacific coast of the United States.
, Oregon to southern Baja California
.
It is abundant in the higher littoral zone on horizontal rock surfaces on both exposed and protected coastlines. It homes at low tide to a specific site where the contours of its shell match the rock surface. It is sometimes found living on Lottia gigantea
.
to rasp microscopic algae and diatom
s off the rock surface. Over time, using the scalloped edge of its shell, it grinds a groove in a rock until the shell makes a perfect fit. This enables it to remain alive under conditions that would otherwise cause desiccation.
, but each occupies a slightly different habitat. L. digitalis tends to occupy vertical rock faces or overhangs and certain horizontal ones clothed by algae and barnacle
s. L. digitalis clump together more often, prefer wave-exposed areas, occupy sites further up the shore and are seldom found in rock pools. Both species move about freely when the tide is up but L. digitalis settles in a different location at each low tide whereas L. scabra tends to home to the same spot. L. scabra has a more rugged outline and grows to fit the rock surface of its home base. The differences in micro-habitat may be explained by its greater tolerance of exposure to desiccation during low tides in less protected sites because it is able to retain water better. If transplanted to unfamiliar territory, each species soon reselects its typical base habitat.
In an experiment, when these two species were caged together with only vertical surfaces available, it was found that L. scabra grew at a much slower rate and achieved a much smaller maximum size than similar limpets in control plots. It seems that the ability of L. digitalis to respond to seasonal changes by moving up and down the shore and utilising resources better give it an edge over the more static species which remains for life in its restricted home range. L. scabra is less able to compete under optimal conditions and is therefore restricted to horizontal, more-dessicating habitats.
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, a marine gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
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 :...
. It is found on the Pacific coast of the United States.
Description
L. scabra grows to a length of about thirty-five millimetres and has conspicuous rugged radial ribs with darker-coloured interspaces and a boldly scalloped margin. The apex is a quarter of the way across the shell and the anterior slope is neither concave nor convex. The shell is a mottled grey and tan colour and the head and the side of foot are white with black spots.Distribution and habitat
L. scabra is found on the Pacific coast of North America from Cape AragoCape Arago State Park
Cape Arago State Park is a state park in the U.S. state of Oregon, administered by the Oregon Parks and Recreation Department....
, Oregon to southern Baja California
Baja 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...
.
It is abundant in the higher littoral zone on horizontal rock surfaces on both exposed and protected coastlines. It homes at low tide to a specific site where the contours of its shell match the rock surface. It is sometimes found living on Lottia gigantea
Lottia gigantea
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...
.
Biology
L. scabra lives on the shoreline often above high water mark in the splash zone. When the rock is wet it moves about and uses its radulaRadula
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...
to rasp microscopic algae and diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...
s off the rock surface. Over time, using the scalloped edge of its shell, it grinds a groove in a rock until the shell makes a perfect fit. This enables it to remain alive under conditions that would otherwise cause desiccation.
Behaviour
At Mission Point on the California coast, L. scabria coexists with the similar species, Lottia digitalisLottia digitalis
Lottia digitalis or the ribbed limpet is a species of sea snail, a true limpet, a marine gastropod mollusk in the family Lottiidae. These limpets are usually found on the surface of rocks in the high intertidal region on the coastal fringes of the north east Pacific Ocean.-Description:This limpet...
, but each occupies a slightly different habitat. L. digitalis tends to occupy vertical rock faces or overhangs and certain horizontal ones clothed by algae and 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. L. digitalis clump together more often, prefer wave-exposed areas, occupy sites further up the shore and are seldom found in rock pools. Both species move about freely when the tide is up but L. digitalis settles in a different location at each low tide whereas L. scabra tends to home to the same spot. L. scabra has a more rugged outline and grows to fit the rock surface of its home base. The differences in micro-habitat may be explained by its greater tolerance of exposure to desiccation during low tides in less protected sites because it is able to retain water better. If transplanted to unfamiliar territory, each species soon reselects its typical base habitat.
In an experiment, when these two species were caged together with only vertical surfaces available, it was found that L. scabra grew at a much slower rate and achieved a much smaller maximum size than similar limpets in control plots. It seems that the ability of L. digitalis to respond to seasonal changes by moving up and down the shore and utilising resources better give it an edge over the more static species which remains for life in its restricted home range. L. scabra is less able to compete under optimal conditions and is therefore restricted to horizontal, more-dessicating habitats.