''Janthina'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of small to medium-sized

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

planktonic Plankton are the diverse collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they pro ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s, marine

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 ...

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

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Epitoniidae Wentletraps are small, often white, very high-spired, predatory or ectoparasitic sea snails, marine gastropod mollusks in the family Epitoniidae.Gofas, S. (2010). Epitoniidae. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusc ...

.Gofas, S. (2011). Janthina Röding, 1798. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138092 on 2011-11-01

Distribution

Species in this genus occur worldwide in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

, subtropical and warm seas.

Description

These snails are

and live at the surface of the ocean. Adult snails may not be capable of swimming, and die when they are detached from their rafts; ''

Janthina janthina ''Janthina janthina'' is a species of holoplanktonic sea snail, a marine gastropod mollusk in the family Epitoniidae. Its common names include violet sea-snail, common violet snail, large violet snail and purple storm snail. Distribution Thi ...

'' larvae, however, actively swim in the water column. The adult snails prey upon (and live near to) one of several species of pelagic animals loosely known as jellyfish. More specifically they eat the

medusae Jellyfish, also known as sea jellies or simply jellies, are the medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals, althoug ...

of free-swimming

Cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

, in particular the genus known as "by-the-wind sailors", ''

Velella ''Velella'' is a monospecific genus of hydrozoa in the family Porpitidae. Its only known species is ''Velella velella'', a cosmopolitan (widely distributed) free-floating hydrozoan that lives on the surface of the open ocean. It is commonly kn ...

''. The snails are able to float securely because they create a raft of clear

chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...

around air bubbles formed near the ocean surface. They anchor to this raft using their

foot The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...

. The snails do not have an operculum. These snails are frequently washed ashore during storms. The common names for this genus derive from the light purple or violet color of the shells and the violet-colored bodies. The other genus in the family, ''

Recluzia ''Recluzia'' is a genus of small to medium-sized pelagic or planktonic sea snails, marine gastropod molluscs in the family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity ...

'', has olive-tan colored shells.

Species

The five extant species of the genus ''Janthina'' File:Janthina exigua 01.jpg, ''Janthina exigua'' File:Janthina globosa 01.JPG, ''Janthina globosa'' File:Janthina janthina 01.JPG, ''Janthina janthina'' File:Janthina pallida 01.JPG, ''Janthina pallida'' File:Janthina umbilicata 01.jpg, ''Janthina umbilicata''

This genus has accumulated a very large number of species names over the centuries. Most of the names that have been given are in fact

synonym A synonym is a word, morpheme, or phrase that means precisely 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 a ...

s of just a few species which have world-wide distributions in tropical waters. Experts disagree about some details of the synonymy. Species within the genus ''Janthina'' include:Gofas, S. (2009). ''Janthina'' Röding, 1798. In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2009) World Marine Mollusca database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138092 on 2010-05-16 * † ''

Janthina chavani ''Janthina'' is a genus of small to medium-sized pelagic or planktonic sea snails, marine (ocean), marine gastropod molluscs in the family (biology), family Epitoniidae.Gofas, S. (2011). Janthina Röding, 1798. Accessed through: World Register of ...

'' (Ludbrook, 1978) * '' Janthina exigua''

Lamarck Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist, biologist, academic, and soldier. He was an early proponent of the idea that biolo ...

, 1816 - dwarf janthina * '' Janthina globosa'' Swainson, 1822 * ''

'' (

Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

1758 Events January–March * January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of ''Systema Naturae'', the starting point of modern zoologic ...

) *† '' Janthina krejcii'' Beu, 2017 * '' Janthina pallida'' W. Thompson, 1840 * † '' Janthina typica'' (Bronn, 1861) * '' Janthina umbilicata'' d'Orbigny, 1841 ;Species brought into synonymy: * ''Janthina affinis'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina africana'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina alba'' Anton, 1838: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina balteata'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina bicolor'' Menke, 1828: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina bicolor'' O. G. Costa, 1830: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina bifida'' Nuttall, 1850: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina britannica'' Forbes & Hanley, 1853: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina capreolata'' Montrouzier, 1860: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina carpenteri'' Mörch, 1860: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina casta'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina coeruleata'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina communis'' Lamarck, 1822: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina contorta'' Carpenter, 1857: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina costae'' Mörch, 1860: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina decollata'' Carpenter, 1857: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina depressa'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina elongata'' ic synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina fibula'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina fragilis'' Lamarck, 1801: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina globosa'' Blainville, 1822: synonym of ''Janthina umbilicata'' d'Orbigny, 1840 * ''Janthina grandis'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina incisa'' Philippi, 1848: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina involuta'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina iricolor'' Reeve, 1858: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina jehennei'' (Petit de la Saussaye, 1853): synonym of '' Recluzia jehennei'' Petit de la Saussaye, 1853 * ''Janthina laeta'' Monterosato, 1884: synonym of ''Janthina pallida'' W. Thompson, 1840 * ''Janthina megastoma'' A. Adams, 1861: synonym of ''Janthina umbilicata'' d'Orbigny, 1840 * ''Janthina nana'' Gray, 1842: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina nitens'' Menke, 1828: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina nitida'' A. Adams, 1861: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina orbignyi'' Mörch, 1860: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina patula'' Philippi, 1844: synonym of ''Janthina pallida'' W. Thompson, 1840 * ''Janthina payraudeaui'' Locard, 1900: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina penicephela'' Peron, 1824: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina planispirata'' A. Adams & Reeve, 1848: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina prolongata'' Blainville, 1822: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina rosea'' Anton, 1838: synonym of ''Janthina pallida'' W. Thompson, 1840 * ''Janthina roseala'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina roseola'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina rotundata'' Dillwyn, 1840: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina smithiae'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina splendens'' Monterosato, 1884: synonym of ''Janthina globosa'' Swainson, 1822 * ''Janthina striata'' Montrouzier, 1860: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina striolata'' A. Adams & Reeve, 1848: synonym of ''Janthina pallida'' W. Thompson, 1840 * ''Janthina striulata'' Carpenter, 1857: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina trochoidea'' Reeve, 1858: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina vinsoni'' Deshayes, 1863: synonym of ''Janthina exigua'' Lamarck, 1816 * ''Janthina violacea'' Röding, 1798: synonym of ''Janthina janthina'' (Linnaeus, 1758) * ''Janthina vulgaris'' Gray, 1847: synonym of ''Janthina janthina'' (Linnaeus, 1758)

References

* Laursen, D. 1953. ''The genus Ianthina: A monograph''. Dana Report 38: 1-40, pl. 1

External links

Röding P.F. (1798). Museum Boltenianum sive Catalogus cimeliorum e tribus regnis naturæ quæ olim collegerat Joa. Fried Bolten, M. D. p. d. per XL. annos proto physicus Hamburgensis. Pars secunda continens Conchylia sive Testacea univalvia, bivalvia & multivalvia. Trapp, Hamburg. viii, 199 pp

Montfort P. [Denys de]. (1808-1810). Conchyliologie systématique et classification méthodique des coquilles. Paris: Schoell. Vol. 1: pp. lxxxvii + 409 [1808]. Vol. 2: pp. 676 + 16

Gistel, Johannes [Nepomuk Franz Xaver]. (1848). Naturgeschichte des Tierreichs: für höhere Schulen. [text book]. 1-216, i-xvi, Plates 1-32. Stuttgart. Scheitlin & Krais.

Mörch, O. A. L. (1860). Matériaux pour servir à l'histoire de la famille des Janthines. Journal de Conchyliologie. 8 (3): 261-285

Iredale, T. (1929). Queensland molluscan notes, no. 1. Memoirs of the Queensland Museum. 9(3): 261-297, pls 30-31

Kaim, A.; Tucholke, B. E.; Warén, A. (2012). A new Late Pliocene large provannid gastropod associated with hydrothermal venting at Kane Megamullion, Mid-Atlantic Ridge. Journal of Systematic Palaeontology. 10(3): 423-433

Beu A.G. (2017). Evolution of Janthina and Recluzia (Mollusca: Gastropoda: Epitoniidae). Records of the Australian Museum. 69(3): 119-222

Gary Rosenberg's Malacolog 4.1.1 info on this genus in the Western Atlantic
{{Taxonbar, from=Q3168326 Epitoniidae Taxa named by Peter Friedrich Röding