Scotch Bonnet (shell)
Encyclopedia
Semicassis granulata, also known as Phalium granulatum, common name
s the Scotch bonnet or ridged bonnet, is a medium-sized species
of sea snail
, a marine
gastropod mollusk in the subfamily Cassinae
.
This species is found in the tropical and subtropical Western Atlantic Ocean
, from North Carolina
to Uruguay
. It is the most common species in this subfamily in North America.
These snails are predators; they search for their food on sandy stretches of the ocean floor, where they consume echinoderms such as sand dollar
s, sea biscuits, and other sea urchin
s.
In 1965, the shell of this species was named a state symbol of North Carolina, making this the first state to designate an official state shell.
In the past this species has sometimes been confused with Semicassis undulata
, a similar-looking Mediterranean species.
. The specific epithet granulata is derived from the Latin word grana meaning grain. Here it is used in the diminutive form, meaning granulated, or covered in granules, i.e. small grains or pellets, referring to the shell sculpture
.
"Scotch bonnet
" because of a vague resemblance to a tam o'shanter, a traditional tartan hat that used to be commonly worn in Scotland
. The shell has a pattern of square or rectangular brown or tan patches. The shell can sometimes be smooth except for growth lines, but in other individuals it can have a sculpture of incised spiral grooves and even weak axial ribs which, together with the colored patches of the shell, create an effect that is somewhat reminiscent of the patterns of a Scottish plaid.
As mentioned above, the shell is variable in surface texture, some shells being more granulated and even having nodules on the shoulders of the whorls, and some other shells being much smoother.
What has often been considered to be merely a smooth variety of this species was given the name: cicatricosa by Johann Friedrich Gmelin
in 1791. If this is indeed only a variety, it has no taxonomic validity. However, currently (2010) Dr. Gary Rosenberg of the ANSP
is listing Semicassis cicatricosa as a separate species on his database Malacolog 4.1.1.
The shell form that has pronounced nodules on the shoulder of the whorls was named form peristephes Pilsbry & Mcgintyi, 1939. http://www.jaxshells.org/piphal.htm
A similar-looking species from the Mediterranean Semicassis undulata
, also named by Gmelin in 1791, has been mistakenly reported from the Western Atlantic but does not occur there. There has been some confusion especially in the popular literature about which name should be applied to which of these two species.
:
This species has apparently not been reported as occurring in the Lesser Antilles
.
, several times at different growth stages. The snail rests between each stage of growth. When it begins to grow again, the snail usually absorbs the entire outer lip. In some cases, especially in deep water, the Scotch bonnet does not absorb the outer lip completely, leaving behind a varix
on the whorls of the mature shell.
The more food a Scotch bonnet consumes during its lifetime, the more elaborate its shell, the glossier its sheen, and the brighter its colors.
The egg-shaped shell of this species usually grows to 2 to 4 in (5.1 to 10.2 cm) in length. The maximum recorded shell
length is 121 mm. The shells of the adult females are larger than those of the males. The sturdy shell of the adult snail has approximately five whorls with coiled spiral grooves crossed by mostly rather faint growth lines.
As is the case in all snails, the final whorl (the body whorl
) is the largest and contains most of the animal’s vital organs. The shell
has a large aperture
, with a thick and toothed outer lip. The inner lip of the aperture has many "pimple-like" bumps on the parietal shield or parietal callus
near the siphonal notch
.
These snails are often found in association with the offshore Atlantic calico scallop
beds, probably attracted by abundant food. Shipwrecks also seem to provide a good habitat for this species.
larvae. The eggs hatch as shell-less free swimming microscopic veliger
s (molluscan larvae) that are carried by the ocean currents.
Growth is slow and the veligers are carried by the ocean currents for up to 14 weeks. As the veligers mature and become juvenile snails, they develop a shell and sink to the ocean floor. The mantle secretes the shell, with growth beginning at the apex and typically rotating clockwise. As the shell matures, the mantle continues to secrete shell material. Scotch bonnets complete maturation in one to six years. However, some have lived more than six years.
are predators of this species. They crush the shell, eating the soft internal organs and muscle tissue. The snail's defense mechanism is to draw its body into the shell. The operculum
may provide some protection against smaller predatory species.
s. On the coast of the Caraguatatuba
region of Brazil
, a study of shell use in the hermit crab species Isocheles sawayai, family Diogenidae, was carried out. This study revealed that 11.5% of the population of these hermit crabs were using shells of Semicassis granulata. The selection of shell type was reported as not being random, but was instead described as being influenced by the weight, size, shape and internal volume of the shell, the occurrence of exobionts on the crab, and the degree of resistance the shell offered to predation and desiccation.
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...
s the Scotch bonnet or ridged bonnet, is a medium-sized 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 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 mollusk in the subfamily Cassinae
Cassinae
Cassidae is a taxonomic family of medium-sized, large and sometimes very large sea snails commonly called helmet snails or bonnet snails. These are marine gastropod mollusks in the superfamily Tonnoidea and the clade Littorinimorpha....
.
This species is found in the tropical and subtropical Western Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, from North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
to Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
. It is the most common species in this subfamily in North America.
These snails are predators; they search for their food on sandy stretches of the ocean floor, where they consume echinoderms such as sand dollar
Sand dollar
The term Sand dollar refers to species of extremely flattened, burrowing echinoids belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as sea biscuits...
s, sea biscuits, and other sea urchin
Sea urchin
Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...
s.
In 1965, the shell of this species was named a state symbol of North Carolina, making this the first state to designate an official state shell.
In the past this species has sometimes been confused with Semicassis undulata
Semicassis undulata
Semicassis undulata is a medium-sized species of sea snail, a marine gastropod mollusc in the subfamily Cassinae.This is a Mediterranean species. It has sometimes been confused with the rather similar Western Atlantic species, Semicassis granulata....
, a similar-looking Mediterranean species.
Scientific name
The word semi means half, and cassis means a metal helmetHelmet
A helmet is a form of protective gear worn on the head to protect it from injuries.Ceremonial or symbolic helmets without protective function are sometimes used. The oldest known use of helmets was by Assyrian soldiers in 900BC, who wore thick leather or bronze helmets to protect the head from...
. The specific epithet granulata is derived from the Latin word grana meaning grain. Here it is used in the diminutive form, meaning granulated, or covered in granules, i.e. small grains or pellets, referring to the shell sculpture
Sculpture (mollusc)
The sculpture of a mollusc shell is the three-dimensional ornamentation on the outer surface, as distinct from the basic shape of the shell itself or colouration. Sculpture may be concave as well as convex. Sometimes it has microscopic detail. Sculpture refers to the calcareous outer layer, not the...
.
Common name
The shell of this species was given the common nameCommon 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...
"Scotch bonnet
Bonnet (headgear)
Bonnets are a variety of headgear for both sexes, which have in common only the absence of a brim. Bonnet derives from the same word in French, where it originally indicated a type of material...
" because of a vague resemblance to a tam o'shanter, a traditional tartan hat that used to be commonly worn in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...
. The shell has a pattern of square or rectangular brown or tan patches. The shell can sometimes be smooth except for growth lines, but in other individuals it can have a sculpture of incised spiral grooves and even weak axial ribs which, together with the colored patches of the shell, create an effect that is somewhat reminiscent of the patterns of a Scottish plaid.
Taxonomy
This species was named and described by the Austrian scientist Ignaz von Born in 1778.As mentioned above, the shell is variable in surface texture, some shells being more granulated and even having nodules on the shoulders of the whorls, and some other shells being much smoother.
What has often been considered to be merely a smooth variety of this species was given the name: cicatricosa by Johann Friedrich Gmelin
Johann Friedrich Gmelin
Johann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...
in 1791. If this is indeed only a variety, it has no taxonomic validity. However, currently (2010) Dr. Gary Rosenberg of the ANSP
Academy of Natural Sciences
The Academy of Natural Sciences of Drexel University, formerly Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the New World...
is listing Semicassis cicatricosa as a separate species on his database Malacolog 4.1.1.
The shell form that has pronounced nodules on the shoulder of the whorls was named form peristephes Pilsbry & Mcgintyi, 1939. http://www.jaxshells.org/piphal.htm
A similar-looking species from the Mediterranean Semicassis undulata
Semicassis undulata
Semicassis undulata is a medium-sized species of sea snail, a marine gastropod mollusc in the subfamily Cassinae.This is a Mediterranean species. It has sometimes been confused with the rather similar Western Atlantic species, Semicassis granulata....
, also named by Gmelin in 1791, has been mistakenly reported from the Western Atlantic but does not occur there. There has been some confusion especially in the popular literature about which name should be applied to which of these two species.
Distribution
There are published records of Semicassis granulata from the following areas of the Western Atlantic OceanAtlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
:
- The East Coast of the USAEast Coast of the United StatesThe East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...
: in North CarolinaNorth CarolinaNorth Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, South CarolinaSouth CarolinaSouth Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
and FloridaFloridaFlorida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
in East Florida, West Florida, and the Florida Keys - The Gulf Coast of the USA: in LouisianaLouisianaLouisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
and TexasTexasTexas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in... - The CaribbeanCaribbeanThe Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
Coast of Central America: in MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
in Quintana RooQuintana RooQuintana Roo officially Estado Libre y Soberano de Quintana Roo is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 10 municipalities and its capital city is Chetumal....
, also in NicaraguaNicaraguaNicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
, Costa RicaCosta RicaCosta Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
, PanamaPanamaPanama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, ColombiaColombiaColombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
and in VenezuelaVenezuelaVenezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
in the Gulf of VenezuelaGulf of VenezuelaThe Gulf of Venezuela is a gulf of the Caribbean Sea bounded by the Venezuelan states of Zulia and Falcón and by Guajira Department, Colombia...
, CaraboboCaraboboCarabobo State is one of the 23 states of Venezuela, located in the north of the country, about two hours by car from Caracas. The capital city of this state is Valencia, which is also the country's main industrial center. The state's area is 4,650 km² and had an estimated population of...
, SucreSucreSucre, also known historically as Charcas, La Plata and Chuquisaca is the constitutional capital of Bolivia and the capital of the department of Chuquisaca. Located in the south-central part of the country, Sucre lies at an elevation of 2750m...
, Isla MargaritaIsla MargaritaMargarita Island is the largest island of the state of Nueva Esparta in Venezuela, situated in the Caribbean Sea, off the northeastern coast of the country. The state also contains two other smaller islands: Coche and Cubagua. The capital city of Nueva Esparta is La Asunción, located in a river...
and Los Testigos IslandsLos Testigos IslandsLos Testigos Islands are a group of islands in the southeastern Caribbean Sea. They are a part of the Dependencias Federales of Venezuela.-Geography:... - BermudaBermudaBermuda is a British overseas territory in the North Atlantic Ocean. Located off the east coast of the United States, its nearest landmass is Cape Hatteras, North Carolina, about to the west-northwest. It is about south of Halifax, Nova Scotia, Canada, and northeast of Miami, Florida...
- The Greater AntillesGreater AntillesThe Greater Antilles are one of three island groups in the Caribbean. Comprising Cuba, Jamaica, Hispaniola , and Puerto Rico, the Greater Antilles constitute almost 90% of the land mass of the entire West Indies.-Greater Antilles in context :The islands of the Caribbean Sea, collectively known as...
, in CubaCubaThe Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
, JamaicaJamaicaJamaica is an island nation of the Greater Antilles, in length, up to in width and 10,990 square kilometres in area. It is situated in the Caribbean Sea, about south of Cuba, and west of Hispaniola, the island harbouring the nation-states Haiti and the Dominican Republic...
and Puerto RicoPuerto RicoPuerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an... - The Atlantic coast of South AmericaSouth AmericaSouth America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, in Surinam, in BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
in Amapa, Maranhao, Ceara, Rio Grande do Norte, Pernambuco, Alagoas, Bahia, Espirito Santo, Rio de Janeiro, São Paulo, Parana and Santa Catarina, and also in UruguayUruguayUruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
This species has apparently not been reported as occurring in the Lesser Antilles
Lesser Antilles
The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...
.
Shell description
It takes approximately six years for a Scotch bonnet to mature. The shell develops the thick outer lip characteristic of the subfamily CassinaeCassinae
Cassidae is a taxonomic family of medium-sized, large and sometimes very large sea snails commonly called helmet snails or bonnet snails. These are marine gastropod mollusks in the superfamily Tonnoidea and the clade Littorinimorpha....
, several times at different growth stages. The snail rests between each stage of growth. When it begins to grow again, the snail usually absorbs the entire outer lip. In some cases, especially in deep water, the Scotch bonnet does not absorb the outer lip completely, leaving behind a varix
Varix (mollusc)
A varix is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs.It is a thickened axial ridge in the shell of some families of gastropods. A varix is located at intervals around the whorl, and is formed by considerable thickening of the outer lip at a resting stage...
on the whorls of the mature shell.
The more food a Scotch bonnet consumes during its lifetime, the more elaborate its shell, the glossier its sheen, and the brighter its colors.
The egg-shaped shell of this species usually grows to 2 to 4 in (5.1 to 10.2 cm) in length. The maximum recorded shell
Gastropod 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...
length is 121 mm. The shells of the adult females are larger than those of the males. The sturdy shell of the adult snail has approximately five whorls with coiled spiral grooves crossed by mostly rather faint growth lines.
As is the case in all snails, the final whorl (the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
) is the largest and contains most of the animal’s vital organs. The shell
Gastropod 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 a large aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
, with a thick and toothed outer lip. The inner lip of the aperture has many "pimple-like" bumps on the parietal shield or parietal callus
Parietal callus
A parietal callus is a feature of the shell anatomy of some groups of snails, i.e. gastropods. It is a thickened calcareous deposit which may be present on the parietal wall of the aperture of the adult shell. The parietal wall is the margin of the aperture and part of the wall of the body whorl...
near the siphonal notch
Siphonal notch
A siphonal notch is a feature of the shell anatomy in some sea snails, marine gastropod mollusks.In these particular groups of sea snails the animal has a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which...
.
Habitat
Scotch bonnets live on shelly sand in moderately shallow water. Shelly sand refers to an abundance of shell fragments mixed in with the sand, and it is typically found where ocean currents are strong. The Atlantic Ocean, especially off the coast of North Carolina, has very strong currents. Divers and local fisherman frequently find Scotch bonnets at depths of about 50 to 150 ft (15.2 to 45.7 m); however, live specimens can be found in depths from 0 to 94 m (0 to 308.4 ft). Empty shells have been found in depths of up to 97 metres (318.2 ft).These snails are often found in association with the offshore Atlantic calico scallop
Atlantic calico scallop
The Atlantic calico scallop, Argopecten gibbus, is a species of medium-sized edible saltwater clam, specifically a scallop, a marine bivalve mollusk in the family Pectinidae, the scallops....
beds, probably attracted by abundant food. Shipwrecks also seem to provide a good habitat for this species.
Life cycle
During the spring, favorable food supplies, adequate light, and optimum water temperature provide conditions for breeding and early growth. At this time, the female deposits hundreds of egg capsules in towers about 4 to 5 in (10.2 to 12.7 cm) high. The male fertilizes these eggs. After fertilization, the eggs develop into trochophoreTrochophore
A trochophore is a type of free-swimming planktonic marine larva with several bands of cilia.By moving their cilia rapidly, a water eddy is created. In this way they control the direction of their movement...
larvae. The eggs hatch as shell-less free swimming microscopic veliger
Veliger
A veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...
s (molluscan larvae) that are carried by the ocean currents.
Growth is slow and the veligers are carried by the ocean currents for up to 14 weeks. As the veligers mature and become juvenile snails, they develop a shell and sink to the ocean floor. The mantle secretes the shell, with growth beginning at the apex and typically rotating clockwise. As the shell matures, the mantle continues to secrete shell material. Scotch bonnets complete maturation in one to six years. However, some have lived more than six years.
Predators
Crabs like the blue crab and Florida stone crabFlorida stone crab
The Florida stone crab, Menippe mercenaria, is a crab found in the western North Atlantic, from Connecticut to Belize, including Texas, the Gulf of Mexico, Cuba and the Bahamas that is widely caught for food.-Description:...
are predators of this species. They crush the shell, eating the soft internal organs and muscle tissue. The snail's defense mechanism is to draw its body into the shell. The operculum
Operculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
may provide some protection against smaller predatory species.
Use by other invertebrates
After death, the empty shell of this sea snail is often used by hermit crabHermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
s. On the coast of the Caraguatatuba
Caraguatatuba
Caraguatatuba, widely known by its abbreviation Caraguá, is a city in the eastern part of the southern state of São Paulo in Brazil. The name comes from the Tupi language and one of the words includes tuba meaning many. Caraguatatuba is the largest city of São Paulo north shore.The economy of the...
region of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, a study of shell use in the hermit crab species Isocheles sawayai, family Diogenidae, was carried out. This study revealed that 11.5% of the population of these hermit crabs were using shells of Semicassis granulata. The selection of shell type was reported as not being random, but was instead described as being influenced by the weight, size, shape and internal volume of the shell, the occurrence of exobionts on the crab, and the degree of resistance the shell offered to predation and desiccation.
Human use
In 1965, the state of North Carolina named the Scotch bonnet as its official state shell, in honor of the abundance of Scottish settlers that founded the state. With this designation, North Carolina became the first state in the USA to have a state shell.External links
- Jacksonville shell club, shell images
- Phalium granulatum info at CLEMAN
- http://books.google.cz/books?id=K0hVJTLfGbMC&lpg=PT259&ots=NZlz5K1JnB&dq=Phalium%20granulatum%20and%20Phalium%20cicatricosum&pg=PT259#v=onepage&q=Phalium%20granulatum%20and%20Phalium%20cicatricosum&f=false - in Pleistocene
- Abbott, American Seashells, 1954, pages 192-193