''Calliostoma ligatum'',

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 con ...

the blue top snail, is a small

prosobranch Prosobranchia was a large Taxonomy (biology), taxonomic Class (biology), subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyly, polyphyletic (consis ...

trochid

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Calliostomatidae Calliostomatidae is a family of sea snails within the superfamily Trochoidea and the clade Vetigastropoda.Gofas, S. (2013). Calliostomatidae. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetail ...

, the

Calliostoma ''Calliostoma'' is a genus of small to medium-sized sea snails with gills and an operculum, marine gastropod molluscs within the family Calliostomatidae, the Calliostoma top snails. Previously this genus was placed within the family Trochid ...

top snails.

Description

The conical, solid shell has well-rounded globose whorls with six to eight smooth spiral cords per whorl and no umbilicus. Its base is flattened. The surface is encircled by numerous spiral smooth riblets, their interstices closely finely obliquely striate. There are usually seven to nine riblets on the penultimate

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagra ...

, about nine on the base. The

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spire ...

is conic. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics) A-Bomb Abomination Absorbing Man Abraxas Abyss Abyss is the name of two characters appearing in Ameri ...

is acute. The sutures are impressed. There are about seven, convex whorls. The

body whorl The body whorl is part of the morphology (biology), morphology of the gastropod shell, shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk ...

is rounded (or a trifle angled) around the lower part, slightly convex beneath. The oblique aperture is rounded. The outer lip is fluted within, with a beveled opaque white submargin. The throat is pearly and iridescent;. The simple

columella Lucius Junius Moderatus Columella (, Arabic: ) was a prominent Roman writer on agriculture in the Roman Empire. His in twelve volumes has been completely preserved and forms an important source on Roman agriculture and ancient Roman cuisin ...

is arcuate. The base color is chocolate brown to mauve with light tan raised cords, and the

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

is pearly white. The

is darked and usually purple. The shell is relatively heavy for its size, and its length and width are roughly equal. Length and width up to 24 mm.American Seashells (Second Edition, 1974), R. Tucker Abbott, p. 48, Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
(described as ''Calliostoma costatum'')

Distribution

Found from

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...

, California.

Reproduction and development

''Calliostoma ligatum'' is a broadcast spawner. Snails spawned in the laboratory in the

San Juan Islands The San Juan Islands is an archipelago in the Pacific Northwest of the United States between the U.S. state of Washington and Vancouver Island, British Columbia, Canada. The San Juan Islands are part of Washington state, and form the core of ...

, WA, USA, during the months of February, March, and April, but only in water that was at least 10 °C. Females release eggs in delicate strands of mucus that break down soon after release. These strands are 1-3mm wide and contain 1-4 eggs across the strand. Ten to ninety eggs are released per pulse, with multiple pulses of eggs released during each spawning event. Males release sperm as a milky white cloud. Fertilization occurs in the water. Eggs are just over 200 um in diameter, and an egg with its protective gelatinous chorion is about 750 um in diameter. Early development proceeds as the

zygote A zygote (; , ) is a eukaryote, eukaryotic cell (biology), cell formed by a fertilization event between two gametes. The zygote's genome is a combination of the DNA in each gamete, and contains all of the genetic information of a new individ ...

undergoes

cleavage Cleavage may refer to: Science * Cleavage (crystal), the way in which a crystal or mineral tends to split * Cleavage (embryo), the division of cells in an early embryo * Cleavage (geology), foliation of rock perpendicular to stress, a result of ...

in the spiral pattern typical of molluscs and other

protostomes Protostomia () is the clade of animals once thought to be characterized by the formation of the organism's mouth before its anus during embryonic development. This nature has since been discovered to be extremely variable among Protostomia's memb ...

. Embryos in culture at 7-9 °C reach the

trochophore A trochophore () 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 in order to capture it more easily. ...

larval stage in 3 days, undergo

torsion Torsion may refer to: Science * Torsion (mechanics), the twisting of an object due to an applied torque * Torsion of spacetime, the field used in Einstein–Cartan theory and ** Alternatives to general relativity * Torsion angle, in chemistry Bio ...

in 4.5–5 days, and hatch 6 days after fertilization.

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 taxono ...

larvae stop swimming and begin crawling 9.5 days after fertilization and undergo

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

into juvenile snails about 12 days after fertilization.

Ecology and behavior

This snail is found frequently on rocks in the low intertidal zone and in the shallow subtidal zone on large

kelp Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a str ...

, especially the giant kelp ''

Macrocystis ''Macrocystis'' is a monospecific genus of kelp (large brown algae) with all species now synonymous with ''Macrocystis pyrifera''. It is commonly known as giant kelp or bladder kelp. This genus contains the largest of all the Phaeophyceae or b ...

''. ''Calliostoma'' eats a variety of items including the kelp it lives on as well as small sessile organisms and other material that live on rocks or kelp surfaces, including

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic animal, aquatic invertebrate animals, nearly all living in sedentary Colony (biology), colonies. Typically about long, they have a spe ...

ns, hydroids,

diatom A diatom (Neo-Latin ''diatoma'') is any member of a large group comprising several Genus, genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. Living diatoms make up a significant portion of Earth's B ...

s, and

detritus In biology, detritus ( or ) is organic matter made up of the decomposition, decomposing remains of organisms and plants, and also of feces. Detritus usually hosts communities of microorganisms that colonize and decomposition, decompose (Reminera ...

. This snail shows a remarkable range of behavioral reactions to other animals. Snails displayed a flight response with movement rates up to 10 cm/min, often accompanied by shell twisting, between 70% and 100% of the time after contact with the following predatory seastars: ''

Leptasterias hexactis ''Leptasterias hexactis'' is a species of starfish in the Family (biology), family Asteriidae, commonly known as the six-rayed star. It is found in the intertidal zone of the western seaboard of the United States. It is a Predation, predator and ...

'', ''

Pycnopodia helianthoides ''Pycnopodia helianthoides'', commonly known as the sunflower sea star, is a large starfish, sea star found in the northeastern Pacific Ocean. The only species of its genus, it is among the largest sea stars in the world, with a maximum arm span ...

'', ''

Pisaster ochraceus ''Pisaster ochraceus'', generally known as the purple sea star, ochre sea star, or ochre starfish, is a common seastar found among the waters of the Pacific Ocean. Identified as a keystone species, ''P. ochraceus'' is considered an important ind ...

'', and ''

Evasterias troschelii ''Evasterias troschelii'' is a species of starfish in the family Asteriidae. Its common names include the mottled star, false ochre sea star and Troschel's true star. It is found in Kamchatka and the north western coast of North America. Taxonom ...

''. Snails either withdrew into their shells, turned away, or fled after contact with the subtidal crab '' Cancer oregonensis''. ''C. ligatum'' showed only a weak response to contact with predatory snails, but ''

Fusitriton oregonensis ''Fusitriton oregonensis'' (Oregon hairy triton) is a species of large predatory sea snail, a marine gastropod mollusk in the family Cymatiidae. The snail was given its specific name ''oregonensis'' (meaning "of Oregon") to honor the Oregon Te ...

'' elicited the strongest response of any snail tested. Contact with ''F. oregonensis'' caused about half of the test subjects to exhibit a flight response while others either bit the predator with their

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

, simply turned away, or showed no response. ''C. ligatum'' frequently uses its radula to rasp on, i.e., bite, its non-predators. ''C.ligatum'' bit the non-predatory seastar '' Henricia leviuscula'' every time they came into contact with each other. After making initial contact the snail reared up, extended its head forward and visibly rasped the upper body wall of ''H. leviuscula'' with its radula. This caused the sea star to move off. ''C. ligatum'' similarly uses its radula to bite, i.e., rasp, on the seastars ''

Solaster stimpsoni ''Solaster stimpsoni'', common names Stimpson's sun star, sun star, orange sun star, striped sunstar, and sun sea star, is a species of starfish in the family Solasteridae. It was first described by Addison Emery Verrill in 1880. Description ' ...

'' about 60% of the time, and ''

Dermasterias imbricata The leather star (''Dermasterias imbricata'') is a sea star in the family Asteropseidae found at depths to off the western seaboard of North America. It was first described to science by Adolph Eduard Grube in 1857. Description The leather sta ...

'' about 40% of the time. ''C. ligatum'' also routinely bit (rasped) the snails ''

Ceratostoma foliatum ''Ceratostoma foliatum'', or leafy hornmouth is a species of medium to large sea snail, a marine (ocean), marine gastropod mollusk in the family Muricidae, the rock snails. Distribution This species lives in the Eastern Pacific. Known from Cal ...

'', '' Searlesia dira'' and '' Amphissa columbiana'' which caused these snails to move away from ''C. ligatum''.

References

External links

* https://scholarsbank.uoregon.edu/xmlui/bitstream/handle/1794/6867/Lane.PDF?sequence=1
''Calliostoma ligatum'' (Gould, 1849)
Wallawalla University * {{Taxonbar, from=Q2212346 ligatum Gastropods described in 1849