''Margarites helicinus'',

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 contrast ...

the helicina margarite or spiral margarite, is a

species In biology, a species is the basic unit of 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 the appropriate s ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

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 e ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Margaritidae Margaritidae is a family of small sea snails, marine gastropod mollusks in the superfamily Trochoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).Bouchet, P. (2012). Margaritidae. Accessed through: World Register ...

. ''Margarites helicinus'' has been established by Phipps in 1774 and not by Fabricus in 1780 as Winchworth (1932), Sneli (1970) (and others) mention. Dall established in 1919 two varieties, but both have become synonyms of ''Margarites helicinus''. * ''Margarites helicinus'' var. ''elevatus'' Dall, 1919 * ''Margarites helicinus'' var. ''excavatus'' Dall, 1919

Description

The size of the shell varies between 3. mm and 11 mm. The umbilicate, thin shell has a depressed-conoidal shape. It is flesh-colored, with paler at periphery and below the suture, fading into corneous around the umbilicus. The surface is very bright, shining, polished, and smooth except for fine subobsolete concentric lines around the umbilicus. 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. Spires are ...

is conoidal. The

apex The apex is the highest point of something. The word may also refer to: Arts and media Fictional entities * Apex (comics), a teenaged super villainess in the Marvel Universe * Ape-X, a super-intelligent ape in the Squadron Supreme universe *Apex ...

is minute but obtuse. The suture is impressed. The shell contains about 5 convex

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). Whorls in nature File:Photograph and axial plane floral ...

s, the last very rapidly widening, somewhat descending toward the

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 opt ...

. The rounded aperture is oblique, angular above, nacreous inside. The pearly iridescence is often visible through the shell. The narrow umbilicus is profound. Its opening is regularly curved, not separated from the base by a carina.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This marine species occurs near the seashore in circum-arctic waters, in the North Atlantic, in European waters; from the Bering Strait to

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, USA; in the

Sea of Okhotsk The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...

Spawning and development

Spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquati ...

takes place during the spring in the

San Juan Islands The San Juan Islands are 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. Prior to spawning two to four snails move close together, one of these is a female and all others are male. A female release eggs only when in close proximity to a male. Eggs are released in a mucus strand 2–3 eggs wide. Eggs are orange to pinkish red, 180–200 µm in diameter, and each egg is covered by a gelatinous layer 10–30 µm thick. Sperm release is not visible during spawning but must occur since eggs in newly produced egg masses are fertilized. The female uses the leading edge of her foot to form the mucus strand into a globular egg mass 0.5–1.5 cm in diameter. Each egg masses contains 90–1000 eggs, and egg masses are anchored to algal surfaces at both ends of the egg mass. All embryonic and larval development takes place in the egg mass and young emerge as juvenile snails. Development proceeds as eggs undergo

spiral cleavage In embryology, cleavage is the division of cells in the early development of the embryo, following fertilization. The zygotes of many species undergo rapid cell cycles with no significant overall growth, producing a cluster of cells the same size ...

. Timing of development at 7–9 °C proceeds as embryos reached the

gastrula Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of Cell (biology), cells), or in mammals the blastocyst is reorganized into a multilayered structure known as ...

stage 1.3 days after fertilization, the

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 ...

stage 2.1 days after fertilization, the

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 ...

stage 3.3 days after fertilization,

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 ...

between 4.5–5 days after fertilization,

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

at 10.5 days, and hatched and crawled out of the egg mass as a juvenile snail at 12.1 days. Shells of newly emergent juvenile snails are 270–300 µm long.

References

* Phipps, C. J. 1774. ''A Voyage towards the North Pole''. viii + 253 pp., 12 pls. J. Nourse: London. * Gmelin, J. F. 1791. ''Systema naturae per regna tria naturae. Editio decima tertia''. Systema Naturae, 13th ed., vol. 1(6): 3021–3910. Lipsiae. * Montagu, G. 1808. ''Supplement to Testacea Britannica.'' ii+ v + 184 pp., 30 pls. S. Woolmer: Exeter. * Leach, W. E. 1819. ''A list of invertebrate animals, discovered by his majesty's ship Isabella, in a voyage to the Arctic regions.'' A Voyage of Discovery. Appendix II, Zoological Memoranda lxi–lxiv John Murray: London. * Totten, J. G. 1834. ''Description of some new shells, belonging to the coast of New England.'' American Journal of Science and Arts 26: 366–369, 1 pl. * Sowerby, G. B., I. 1838. ''A descriptive catalogue of the species of Leach's genus Margarita''. Malacological and Conchological Magazine 1: 23–27. * Thompson, W. 1844. ''Report on the fauna of Ireland: Div. Invertebrata''. Report of the Thirteenth meeting of the British Association for the Advancement of Science 245–291. * Middendorff, A. T. von. 1848. ''Vorläufige Anzeige einiger neuer Konchylien aus den Geschlectern: Littorina, Tritonium, Bullia, Natica und Margarita''. Bulletin de la Classe Physico-Mathématique de l'Académie Impériale des Sciences de Saint-Pétersbourg 7: col. 241–245 * Middendorff, A. T. von. 1849. ''Beiträge zu einer Malacozoologia Rossica. II. Aufzählung und Beschreibung der zur Meeresfauna Russlands gehörigen einschaler.'' Mémoires de l'Académie Impériale des Sciences de Saint-Pétersbourg, Sciences Naturelles (6)6: 329–516, pls. 1–11. * Jeffreys, J. G. 1865. ''British conchology''. British Conchology 3: i+ 393 pp., frontispiece, 8 pls. John Van Voorst: London * Leche, W. 1878. ''Öfversigt öfver de af Svenska Expeditionerna till Novaja Semlja och Jenissej 1875 och 1876 Insamlade: Hafs-Mollusker''. Kongliga Svenska Vetenskaps-Akademiens Handlingar (2)16(2): 1–86, pls. 1–2 * Smith, E. A. 1899. ''On some Mollusca from Bering Sea, with descriptions of two new species of Trochidae''. Proceedings of the Malacological Society of London 3: 205–207 * Dall, W. H. 1919. ''Descriptions of new species of Mollusca from the North Pacific Ocean in the collection of the United States National Museum''. Proceedings of the United States National Museum 56(2295): 293–371 * Backeljau, T. (1986). ''Lijst van de recente mariene mollusken van België ist of the recent marine molluscs of Belgium'. Koninklijk Belgisch Instituut voor Natuurwetenschappen: Brussels, Belgium. 106 pp. * Turgeon, D.D., et al. 1998. ''Common and scientific names of aquatic invertebrates of the United States and Canada''. American Fisheries Society Special Publication 26 page(s): 60 * Gofas, S.; Le Renard, J.; Bouchet, P. (2001). Mollusca, in: Costello, M.J. et al. (Ed.) (2001). ''European register of marine species: a check-list of the marine species in Europe and a bibliography of guides to their identification.'' Collection Patrimoines Naturels, 50: pp. 180–213 * Kantor Yu.I. & Sysoev A.V. (2006) ''Marine and brackish water Gastropoda of Russia and adjacent countries: an illustrated catalogue''. Moscow: KMK Scientific Press. 372 pp. + 140 pls. page(s): 34 * Gulbin V.V. & Chaban E.M. (2012) ''Annotated list of shell-bearing gastropods of Commander Islands. Part I.'' The Bulletin of the Russian Far East Malacological Society 15–16: 5–30. * Dyntaxa (2013) ''Swedish Taxonomic Database''.

External links

* {{DEFAULTSORT:Margarites Helicinus helicinus Gastropods described in 1774 Taxa named by Constantine Phipps, 2nd Baron Mulgrave