The Scotch bonnet (''Semicassis granulata'') is a medium-sized to large
species
In biology, a species is the basic unit of Taxonomy (biology), 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 ...
of
sea snail, a
marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
gastropod mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is es ...
in the
subfamily Cassinae
The Cassidae are 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.Gof ...
, the helmet shells and bonnet shells. The
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contra ...
"Scotch bonnet" alludes to the general outline and color pattern of the shell, which vaguely resemble a
tam o' shanter, a traditional
Scottish
Scottish usually refers to something of, from, or related to Scotland, including:
*Scottish Gaelic, a Celtic Goidelic language of the Indo-European language family native to Scotland
*Scottish English
*Scottish national identity, the Scottish ide ...
bonnet or cap. The shell is egg-shaped and fairly large, in maximum dimension, with a regular pattern of yellow, orange or brown squarish spots. The surface sculpture of the shell is highly variable: the surface can be smooth and polished, have grooves, be granulated, or even be nodulose on the shoulder of the whorls.
This species lives intertidally and subtidally on sandy substrates, and is found primarily in the tropical and subtropical Western
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth#Surface, Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Afr ...
, from
North Carolina
North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia a ...
to
Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
. It is the most common species in this subfamily in
North America. A similar-appearing sea snail in the
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
and Northern Atlantic Ocean, ''
Semicassis undulata'', is currently considered to be a separate species. The exact
taxonomy
Taxonomy is the practice and science of categorization or classification.
A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...
of ''Semicassis granulata'' has been unclear in the past: as well as the current combination, 38 other combinations and
synonyms
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are ...
exist.
In the spring, the adult females of this species lay eggs in tower-shaped structures. The eggs hatch as
veliger
A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells.
Description
The veliger is the characteristic larva of the gastropod, bivalve and scaphopod ...
larvae, which can float in the
plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...
for up to 14 weeks before settling onto the seabed as tiny snails. Crabs are a predator of this sea snail. After the death of the snails, if the shells are still intact they are often used by
hermit crab
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an a ...
s.
In 1965, in the
US, the Scotch bonnet shell was named as a state symbol of
North Carolina
North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia a ...
, the first designation of a
US state shell.
Etymology
;Scientific name
The
generic name is a combination of the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
prefix ''semi'', meaning half, and noun ''cassis'', meaning
helmet
A helmet is a form of protective gear worn to protect the head. More specifically, a helmet complements the skull in protecting the human brain. Ceremonial or symbolic helmets (e.g., a policeman's helmet in the United Kingdom) without prote ...
. The
specific name of this
taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...
, ''granulata'', is derived from the Latin noun ''grana'' meaning grain. Here it is used in the
diminutive form
A diminutive is a root word that has been modified to convey a slighter degree of its root meaning, either to convey the smallness of the object or quality named, or to convey a sense of intimacy or endearment. A ( abbreviated ) is a word-forma ...
, meaning granulated, or covered in granules, i.e. small grains or pellets, referring to the
shell sculpture.
;Common name
The shell of this species was given the
common name
In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contra ...
"Scotch
bonnet
A Bonnet is a variety of headgear, hat or cap
Specific types of headgear referred to as "bonnets" may include
Scottish
*Blue bonnet, a distinctive woollen cap worn by men in Scotland from the 15th-18th centuries And its derivations:
** Feat ...
" because of a vague resemblance to a tam o' shanter, a traditional
tartan
Tartan ( gd, breacan ) is a patterned cloth consisting of criss-crossed, horizontal and vertical bands in multiple colours. Tartans originated in woven wool, but now they are made in other materials. Tartan is particularly associated with Sc ...
hat which used to be commonly worn in Scotland. The shell has a regular pattern of square or rectangular patches that are orange, tan, or brown in color. 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 on the shell, create an effect that is reminiscent of the pattern of a
Scottish plaid.
Taxonomy
This species was originally named ''Buccinum granulatum'', and was described by the Austrian naturalist
Ignaz von Born
Ignaz Edler von Born, also known as Ignatius von Born ( hu, Born Ignác, ro, Ignațiu von Born, cs, Ignác Born) (26 December 1742 in Alba Iulia, Grand Principality of Transylvania, Habsburg monarchy – 24 July 1791 in Vienna), was a mine ...
in 1778. Born's description is in
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
and reads:
[
:"''Testa ovata, transversim, obsolete sulcata, tessulis luteis seriatim maculata, labio granulato, cauda recurva''".
Translated, this reads:
:"Shell ovate, transversely obscurely sulcate r grooved regularly marked with yellow squares, the lip granulated, the tail recurved"
Since 1778, this ]taxon
In biology, a taxon ( back-formation from '' taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular n ...
has been recombined numerous times into different genera and subgenera
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed betwee ...
. Nearly a century after Born's description, in 1877, the Swedish
Swedish or ' may refer to:
Anything from or related to Sweden, a country in Northern Europe. Or, specifically:
* Swedish language, a North Germanic language spoken primarily in Sweden and Finland
** Swedish alphabet, the official alphabet used b ...
naturalist Otto Andreas Lowson Mörch Otto Andreas Lowson Mörch (his last name also spelled Mørch) (17 May 1828 – 25 January 1878) was a biologist, specifically a malacologist. He lived in Sweden, in Denmark, and in France
France (), officially the French Republic ( ), ...
proposed a new combination and transferred this taxon to the genus ''Cassis'' and subgenus ''Semicassis''. In 1944, the American malacologist William James Clench
William James Clench (24 October 1897 – 22 February 1984) was an American malacologist, professor at Harvard University and curator of the mollusk collection in the malacology department of the Museum of Comparative Zoology at Harvard.
Early ...
recombined the species as ''Phalium (Semicassis) granulatum'', and five years later the Brazilian naturalist Frederico Lange de Morretes Frederico is a given name. It is a form of Frederick, most commonly found in Portuguese.
Literature
* Frederico Barbosa, Brazilian poet
* Frederico Ghisliero, Italian fencer and soldier who wrote his text Regole di molte cavagliereschi esserciti ...
recombined it as ''Semicassis granulatum''. American malacologist Clifton S. Weaver
Clifton may refer to:
People
*Clifton (surname)
* Clifton (given name)
Places
Australia
*Clifton, Queensland, a town
** Shire of Clifton
* Clifton, New South Wales, a suburb of Wollongong
* Clifton, Western Australia
Canada
*Clifton, Nova Sco ...
reallocated it in the subgenus '' Tylocassis'' in 1962, though American malacologist R. Tucker Abbott
Robert Tucker Abbott (September 28, 1919 – November 3, 1995) was an American conchologist (seashells) and malacologist ( molluscs). He was the author of more than 30 books on malacology, which have been translated into many languages.
Abbo ...
recombined it as ''Phalium (Tylocassis) granulatum'' six years later. American malacologist Andrew C. Miller recombined it as ''Phalium granulatum'' in 1983, and German malacologist Kurt Kreipl
Kurt is a male given name of Germanic or Turkish origin. ''Kurt'' or ''Curt'' originated as short forms of the Germanic Conrad, depending on geographical usage, with meanings including counselor or advisor.
In Turkish, Kurt means "Wolf" and is ...
recombined it as ''Semicassis (Semicassis) granulata'' in 1997. The currently accepted combination, ''Semicassis granulata'', was proposed by New Zealand paleontologist Alan Beu
Alan may refer to:
People
*Alan (surname), an English and Turkish surname
*Alan (given name), an English given name
** List of people with given name Alan
''Following are people commonly referred to solely by "Alan" or by a homonymous name.''
* ...
, based on paleontological
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...
data.
Subspecies
There is a similar-looking species, '' Semicassis undulata'', which lives in the Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
and the Macaronesian Islands
Macaronesia (Portuguese: ''Macaronésia,'' Spanish: ''Macaronesia'') is a collection of four volcanic archipelagos in the North Atlantic, off the coasts of Africa and Europe. Each archipelago is made up of a number of Atlantic oceanic island ...
, parts of the northeastern Atlantic. In 1791, that sea snail was given the specific name ''undulata'' by the German naturalist Johann Friedrich Gmelin. In 2015, this taxon was considered to be a subspecies of ''S. granulata'', and therefore was known as ''Semicassis granulata undulata''. ''Semicassis undulata'' has mistakenly been reported from the Western Atlantic Ocean, but does not occur there.[Rosenberg, G. (2012). Semicassis granulata undulata (Gmelin, 1791). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=591482 on 2012-06-17]
Forms
Some Scotch bonnets have a completely smooth and glossy shell. These were thought to be a different species, which was given the name ''cicatricosa'' by Gmelin in 1791. This taxon was recognized for a while, including up until 2010, as a separate species, ''Semicassis cicatricosa''. However, in 2015 this is considered to be only a form
Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens.
Form also refers to:
* Form (document), a document (printed or electronic) with spaces in which to write or enter dat ...
, therefore ''S. cicatricosa'' has become another synonym of ''S. granulata''.
For this smooth and glossy form, the maximum recorded shell length is 60 mm.[Welch, J.J. (2010). "The "Island Rule" and Deep-Sea Gastropods: Re-Examining the Evidence". '' PLoS ONE'' 5(1): e8776. .]
The minimum recorded depth for this form is 0 m; the maximum recorded depth is 6 m.
In 1939, the shell form of ''Semicassis granulata'' which has nodules on the shoulder was named as a subspecies, ''Semicassis cicatricosa peristephes'', by American malacologists Henry G. Pilsbry and Thomas L. Mcginty. This supposed subspecies has since been considered a synonym of ''S. cicatricosa'', and consequently of ''S. granulata''.
Distribution
There are published records of the nominate subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics ( morphology), but that can successfully interbreed. Not all spec ...
''Semicassis granulata granulata'' from several warm-water and tropical areas of the Western Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth#Surface, Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Afr ...
. It is considered the most common species of ''Cassinae
The Cassidae are 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.Gof ...
'' in North America. Regions and countries where this species occurs include the East Coast of the US, in North Carolina
North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia a ...
, South Carolina
)'' Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no)
, anthem = "Carolina";" South Carolina On My Mind"
, Former = Province of South Carolina
, seat = Columbia
, LargestCity = Charleston
, LargestMetro = G ...
, Georgia
Georgia most commonly refers to:
* Georgia (country), a country in the Caucasus region of Eurasia
* Georgia (U.S. state), a state in the Southeast United States
Georgia may also refer to:
Places
Historical states and entities
* Related to t ...
and Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...
(East Florida, West Florida, and the Florida Keys). It has also been recorded on the Gulf Coast of the US, including Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a U.S. state, state in the Deep South and South Central United States, South Central regions of the United States. It is the List of U.S. states and territories by area, 20th-smal ...
and Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
. The species is known to occur in the Caribbean Coast of Central America, including Mexico (Quintana Roo
Quintana Roo ( , ), officially the Free and Sovereign State of Quintana Roo ( es, Estado Libre y Soberano de Quintana Roo), is one of the 31 states which, with Mexico City, constitute the 32 federal entities of Mexico. It is divided into 11 mu ...
), Nicaragua
Nicaragua (; ), officially the Republic of Nicaragua (), is the largest Sovereign state, country in Central America, bordered by Honduras to the north, the Caribbean Sea, Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to ...
, Costa Rica, Panama
Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...
and Colombia, as well as Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in ...
(Gulf of Venezuela
The Gulf of Venezuela is a gulf of the Caribbean Sea bounded by the Venezuelan states of Zulia and Falcón and by La Guajira Department, Colombia. The western side is formed by the Guajira Peninsula. A strait connects it with Maracaibo La ...
, Carabobo
, anthem = ''Carabobo State Anthem, Himno del Estado Carabobo''
, image_map = Carabobo in Venezuela.svg
, map_alt =
, map_caption = Location within Venezuela
, pushpin_map ...
, Sucre
Sucre () is the capital of Bolivia, the capital of the Chuquisaca Department and the 6th most populated city in Bolivia. Located in the south-central part of the country, Sucre lies at an elevation of . This relatively high altitude gives the ...
, Isla Margarita
Margarita Island (, ) is the largest island in the Venezuelan state of Nueva Esparta, situated off the northeastern coast of the country, in the Caribbean Sea. The capital city of Nueva Esparta, La Asunción, is located on the island.
History ...
and Los Testigos Islands
Los Testigos Islands ( es, Islas Los Testigos, Witnesses Islands) are a group of islands in the southeastern Caribbean Sea. They are a part of the ''Dependencias Federales'' (Federal Dependencies) of Venezuela.
Geography
The Los Testigos Islands ...
). It is also found in Bermuda
)
, anthem = " God Save the King"
, song_type = National song
, song = "Hail to Bermuda"
, image_map =
, map_caption =
, image_map2 =
, mapsize2 =
, map_caption2 =
, subdivision_type = Sovereign state
, subdivision_name =
, ...
, the Greater Antilles
The Greater Antilles ( es, Grandes Antillas or Antillas Mayores; french: Grandes Antilles; ht, Gwo Zantiy; jam, Grieta hAntiliiz) is a grouping of the larger islands in the Caribbean Sea, including Cuba, Hispaniola, Puerto Rico, Jamaica, ...
, Cuba
Cuba ( , ), officially the Republic of Cuba ( es, República de Cuba, links=no ), is an island country comprising the island of Cuba, as well as Isla de la Juventud and several minor archipelagos. Cuba is located where the northern Caribbea ...
, Jamaica
Jamaica (; ) is an island country situated in the Caribbean Sea. Spanning in area, it is the third-largest island of the Greater Antilles and the Caribbean (after Cuba and Hispaniola). Jamaica lies about south of Cuba, and west of Hispan ...
and Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...
, and further south in the Atlantic coast of South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the souther ...
, Suriname
Suriname (; srn, Sranankondre or ), officially the Republic of Suriname ( nl, Republiek Suriname , srn, Ripolik fu Sranan), is a country on the northeastern Atlantic coast of South America. It is bordered by the Atlantic Ocean to the north ...
, Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
(Amapá
Amapá () is one of the 26 states of Brazil. It is in the northern region of Brazil. It is the second least populous state and the eighteenth largest by area. Located in the far northern part of the country, Amapá is bordered clockwise by Fr ...
, Maranhão
Maranhão () is a state in Brazil. Located in the country's Northeast Region, it has a population of about 7 million and an area of . Clockwise from north, it borders on the Atlantic Ocean for 2,243 km and the states of Piauí, Tocantins and ...
, Ceará
Ceará (, pronounced locally as or ) is one of the 26 states of Brazil, located in the northeastern part of the country, on the Atlantic coast. It is the eighth-largest Brazilian State by population and the 17th by area. It is also one of th ...
, Rio Grande do Norte
Rio Grande do Norte (, , ) is one of the states of Brazil. It is located in the northeastern region of the country, forming the northeasternmost tip of the South American continent. The name literally translates as "Great Northern River", re ...
, Pernambuco
Pernambuco () is a state of Brazil, located in the Northeast region of the country. With an estimated population of 9.6 million people as of 2020, making it seventh-most populous state of Brazil and with around 98,148 km², being the ...
, Alagoas
Alagoas (, ) is one of the 27 federative units of Brazil and is situated in the eastern part of the Northeast Region. It borders: Pernambuco (N and NW); Sergipe (S); Bahia (SW); and the Atlantic Ocean (E). Its capital is the city of Maceió. ...
, Bahia
Bahia ( , , ; meaning "bay") is one of the 26 states of Brazil, located in the Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo, Minas Gerais, and Rio de Janeiro) and the 5th-largest ...
, Espírito Santo
Espírito Santo (, , ; ) is a state in southeastern Brazil. Its capital is Vitória, and its largest city is Serra. With an extensive coastline, the state hosts some of the country's main ports, and its beaches are significant tourist att ...
, Rio de Janeiro
Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the Rio de Janeiro (state), state of the same name, Brazil's List of Brazilian states by population, third-most populous state, and the List of largest citi ...
, São Paulo
São Paulo (, ; Portuguese for 'Saint Paul') is the most populous city in Brazil, and is the capital of the state of São Paulo, the most populous and wealthiest Brazilian state, located in the country's Southeast Region. Listed by the Ga ...
, Paraná and Santa Catarina), and also in Uruguay
Uruguay (; ), officially the Oriental Republic of Uruguay ( es, República Oriental del Uruguay), is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast; while bordering ...
. As of 2009, this species had apparently not been reported in the literature as occurring in the Lesser Antilles
The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc bet ...
.
In contrast, the species '' Semicassis undulata'' occurs in the Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...
, and parts of the North Atlantic Ocean, including Portugal
Portugal, officially the Portuguese Republic, In recognized minority languages of Portugal:
:* mwl, República Pertuesa is a country located on the Iberian Peninsula, in Southwestern Europe, and whose territory also includes the Macaronesian ...
and the Azores
)
, motto=
( en, "Rather die free than subjected in peace")
, anthem=( en, "Anthem of the Azores")
, image_map=Locator_map_of_Azores_in_EU.svg
, map_alt=Location of the Azores within the European Union
, map_caption=Location of the Azores wi ...
.
Anatomy
;Shell description
The egg-shaped shell of this species usually grows to 40–55 mm in length (1 1/2" - 2 1/8") (the maximum recorded 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 ...
length is 121 mm (4.76 in)).[''Semicassis granulata'' (Born, 1778)](_blank)
Malacolog Version 4.1.1. A Database of Western Atlantic Marine Mollusca. Accessed 14 December 2009. It is thick and solid, with a moderately high spire and rounded body whorl, and adult specimens have approximately five whorls. The protoconch
A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also calle ...
is rounded, colored cream with an orange to brown apex. The teleoconch
The gastropod shell is part of the body of a gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. So ...
is sculptured by spiral grooves crossed by mostly rather faint growth lines.[ Its surface varies in the degree of shell sculpture that is present. Some shells are completely smooth with a high gloss, whereas other shells are grooved. The surface of some shells is granulated, and some even have nodules on the shoulders of the whorls.] Several times at different growth stages, the shell develops a thick outer lip, which is characteristic of the subfamily Cassinae
The Cassidae are 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.Gof ...
. The snail rests between each of these stages of growth, and usually absorbs the entire outer lip before it begins to grow again.[ In some cases, especially in deep water, the Scotch bonnet does not absorb the outer lip completely, leaving behind a ]varix
A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels.
Examples of varices include:
* Varicose veins, large tortuous veins ...
on the whorls of the mature shell.
The shell has a large aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An ...
, with a thick outer lip, and a glossy, oval parietal shield. The outer lip has a series of short, strong lirae, giving it a toothed appearance. The lower part of the inner lip near the 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 ...
has many "pimple-like" bumps or pustules. It has a yellow to brown corneous
Corneous is a biological and medical term meaning horny, in other words made out of a substance similar to that of horns and hooves in some mammals.
The word is generally used to describe natural or pathological anatomical structures made o ...
operculum, with an outline that matches the aperture's contour. The shell is colored pale tan or creamy white, sometimes purplish, with regularly-arranged, orange to light brown rectangular markings[ that often appear faded, even in fresh specimens.] Shells of adult females are larger than those of males.
Ecology
Scotch bonnets are 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 ...
s; they search for their food on sandy stretches of the ocean floor, where they consume echinoderms
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the ...
such as sand dollar
Sand dollars (also known as a sea cookie or snapper biscuit in New Zealand, or pansy shell in South Africa) are species of flat, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are k ...
s, sea biscuits, and other sea urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) ...
s (such as ''Echinocardium cordatum
''Echinocardium cordatum'', also known as the common heart urchin or the sea potato, is a sea urchin in the family Loveniidae. It is found in sub-tidal regions in the NE Atlantic. Other un-named species have been identified as this species from t ...
''), drilling into their tests
Test(s), testing, or TEST may refer to:
* Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities
Arts and entertainment
* ''Test'' (2013 film), an American film
* ''Test'' (2014 film), ...
with the aid of sulfuric acid.
Habitat
''Semicassis granulata'' lives on sandy substrate in moderately shallow water, as well as rocky tide pool
A tide pool or rock pool is a shallow pool of seawater that forms on the rocky intertidal shore. Many of these pools exist as separate bodies of water only at low tide.
Many tide pool habitats are home to especially adaptable animals th ...
s close to the shore. Off the coast of North Carolina, divers and local fisherman frequently find Scotch bonnets at depths of about ; however, live specimens can be found in depths from . Empty shells have been found in depths of up to . These snails are often found in association with the offshore Atlantic calico scallop
''Argopecten gibbus'', the Atlantic calico scallop, is a species of medium-sized edible marine bivalve mollusk in the family Pectinidae, the scallops.
This species was once the basis of an important fishery, but in recent years catches have bee ...
beds, probably attracted by the 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 tower-shaped structures about high.[ The male fertilizes these eggs. After fertilization, the eggs develop into ]trochophore
A trochophore (; also spelled trocophore) is a type of free-swimming planktonic marine larva with several bands of cilia.
By moving their cilia rapidly, they make a water eddy, to control their movement, and to bring their food closer, to captur ...
larvae, and the eggs subsequently hatch as free swimming microscopic veliger
A veliger is the planktonic larva of many kinds of sea snails and freshwater snails, as well as most bivalve molluscs (clams) and tusk shells.
Description
The veliger is the characteristic larva of the gastropod, bivalve and scaphopod ...
larvae, which can be carried some distance on ocean currents.
Growth is slow, and the veligers are carried by the ocean currents for up to 14 weeks. As the veligers mature, they develop their first shell (the smooth protoconch
A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also calle ...
) and turn into very small juvenile snails, at which point they sink to the ocean floor. As is the case in all shelled mollusks, the mantle
A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that.
Mantle may refer to:
*Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear
**Mantle (vesture), an Eastern Orthodox ve ...
is what secretes the shell; shell growth begins at what will later become the apex of the shell, and typically rotates clockwise. As the animal gradually 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
The Scotch bonnet is preyed upon by vertebrates, such as fish, and invertebrates, including crabs such as the blue crab Blue crab may refer to:
* Blue Crab 11, an American sailboat design
* ''Callinectes sapidus'' – Chesapeake or Atlantic blue crab of the West Atlantic, introduced elsewhere
* '' Cardisoma guanhumi'' – blue land crab of the West Atlantic
* ''Disco ...
and the Florida stone crab
The Florida stone crab (''Menippe mercenaria'') is a crab found in the western North Atlantic, from Connecticut to Colombia, including Texas, the Gulf of Mexico, Belize, Mexico Jamaica, Cuba, The Bahamas, and the East Coast of the United States ...
. Crabs can crush the snail's shell, eating the soft internal organs and muscle tissue.[ The snail's only defense mechanism against predation is to draw its body into the shell. By doing so, they can at least partially close the aperture using the operculum.][
]
Use by other invertebrates
After death, the empty shell of this sea snail is often used by hermit crab
Hermit crabs are anomuran decapod crustaceans of the superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit crab, most of which possess an a ...
s. On the coast of the Caraguatatuba
Caraguatatuba, widely known by its abbreviation ''Caraguá'', is a city in the eastern part of the southern state of São Paulo in Brazil. It is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 123,389 (2020 ...
, Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
, a study of shell use in the diogenid hermit crab species '' Isocheles sawayai'' was carried out. This study revealed that 11.5% of the population of these hermit crabs were using shells of ''Semicassis granulata''. The occupation 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 epibiont
An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An epi ...
s such as bryozoans
Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...
on the shell, and the degree of resistance the shell offered to predation and desiccation.
Human use
In 1965, the US 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 US to have a state shell.
Populations of ''S. granulata'' have been suffering a decline due to increased collection and accidental harvesting by commercial fishermen.
References
Further reading
*
*
External links
Jacksonville shell club, shell images
''Phalium granulatum'' info at CLEMAN
- in Pleistocene
* Abbott, American Seashells, 1954
pages 192-193
*
{{Taxonbar, from=Q1972146
Cassidae
Gastropods described in 1778
Taxa named by Ignaz von Born
Symbols of North Carolina