''Limacina'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of swimming

predatory 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 th ...

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 ...

s commonly known as sea butterflies in the family Limacinidae. This genus contains some of the world's most abundant gastropod species.Bouchet, P.; Gofas, S. (2012). Limacina. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138122 on 2012-07-18

Etymological Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the form of words and ...

meaning of the generic name ''Limacina'' is "snail-like". As

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

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 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 ...

s, ''Limacina'' swim by flapping their

parapodia In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed ...

, inspiring 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 contrast ...

sea butterflies. Sea butterflies are part of the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Thecosomata. Sea angels, similar to ''Limacina'', are in the order Gymnosomata. Both of these orders are still referred to as "

pteropods Pteropoda ( common name pteropods, from the Greek meaning "wing-foot") are specialized free-swimming pelagic sea snails and sea slugs, marine opisthobranch gastropods. Most live in the top 10 m of the ocean and are less than 1 cm long. The mo ...

". Sea butterflies of the order Thecosomata have a shell, while sea angels in the order Gymnosomata do not.

Shell description

The shells of ''Limacina'' are well developed, sinistrally coiled, turret-like, and include an operculum. Shell size and thickness vary within the genus. At high latitudes, the diameter of the shell does not exceed 15 mm. At lower latitudes, the diameter varies from 1 to 3 mm.

Description of the soft parts

Two large winglike parapodia, derived from foot tissue, propel these

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

through the water column to overcome negative buoyancy due to the animal's shell. As diel vertical migrators, ''Limacina'' inhabit deeper waters during the day and travel to the surface at night to feed.

Life habits

Feeding habits of ''Limacina'' are characterized by actively feeding on planktonic organisms such as

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

, small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s, gastropod

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s and

diatom A diatom (Neo-Latin ''diatoma''), "a cutting through, a severance", from el, διάτομος, diátomos, "cut in half, divided equally" from el, διατέμνω, diatémno, "to cut in twain". is any member of a large group comprising sev ...

s. These prey items become entangled in a mucosal web (up to 5 cm wide) excreted by the animal that is, in turn, eaten along with the prey items. This net also provides positive buoyancy. Ciliated posterior footlobes and lateral footlobes move food collected by the mucosal web into the mouth. Large aggregations of ''Limacina'' migrating to the surface of the water attract predators such as ''Clione'' (family Clionidae, suborder Gymnosomata),

baleen whale Baleen whales (systematic name Mysticeti), also known as whalebone whales, are a parvorder of carnivorous marine mammals of the infraorder Cetacea (whales, dolphins and porpoises) which use keratinaceous baleen plates (or "whalebone") in their ...

s, various species of

salmonid Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefis ...

s, herring, and

seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...

Species

Species within the genus ''Limacina'' include: * † ''

Limacina atypica ''Limacina'' is a genus of swimming predatory sea snails commonly known as sea butterflies in the family Limacinidae. This genus contains some of the world's most abundant gastropod species.Bouchet, P.; Gofas, S. (2012). Limacina. Accessed throu ...

'' (Laws, 1944) * (recent) '' Limacina bulimoides'' (

d'Orbigny Alcide Charles Victor Marie Dessalines d'Orbigny (6 September 1802 – 30 June 1857) was a French naturalist who made major contributions in many areas, including zoology (including malacology), palaeontology, geology, archaeology and anthropol ...

, 1836) - Bulimoid pteropod. Distribution: Red Sea, Pacific. Length: 1.2 mm. * † '' Limacina erasmiana'' Janssen, 2010Janssen A. W. (2010). "Pteropods (Mollusca, Euthecosomata) from the Early Eocene of Rotterdam (The Netherlands)". '' Scripta Geologica'' 07 http://www.scriptageologica.nl/10/nr007/a09 * † '' Limacina dilatata'' (Koenen, 1892) * † '' Limacina ferax'' (Laws, 1944) * † '' Limacina gormani'' (Curry, 1982) * † '' Limacina guersi'' Janssen, 2010 * (recent) '' Limacina helicina'' (Phipps, 1774) - Helicid pteropod. Type species.Janssen A. W. (2007). "Holoplanktonic Mollusca (Gastropoda: Pterotracheoidea, Janthinoidea, Thecosomata and Gymnosomata) from the Pliocene of Pangasinan (Luzon, Philippines)". '' Scripta Geologica'' 137 http://www.scriptageologica.nl/07/nr135/a02 * (recent) ''

Limacina lesueurii ''Limacina lesueurii'' is a pelagic species of sea snail pteropod (sea butterfly). History The species was first documented in 1826. They have migrated and are now spread across the north to central Atlantic Ocean, and Australasia Austr ...

'' (d'Orbigny, 1836) - Distribution: North America, Western Atlantic. * † '' Limacina limata'' (Marwick, 1926) * † '' Limacina pygmaea'' (Lamarck, 1805) * (recent) '' Limacina rangii'' (d'Orbigny, 1834) * (recent) ''

Limacina retroversa ''Limacina retroversa'' is a species of swimming predatory sea snail in the family Limacinidae, that belongs to the group commonly known as sea butterflies (Thecosomata). There is one subspecies, ''Limacina retroversa australis'' (Eydoux & Sou ...

'' (Fleming, 1823) - Retrovert pteropod. Distribution: North America, Western Atlantic, Arctic Ocean. * † '' Limacina sculptilis'' (Maxwell, 1992) * † '' Limacina taylori'' (Curry, 1965) * (recent) '' Limacina trochiformis'' (d'Orbigny, 1836) - Trochiform pteropod. Distribution: North America, Western Atlantic, Red Sea, Pacific. Length: 1 mm. * † '' Limacina valvatina'' (Reuss, 1867) * † '' Limacina? vegrandis'' Cahuzac & Janssen, 2010Cahuzac B. & Janssen A. W. (2010). "Eocene to Miocene holoplanktonic Mollusca (Gastropoda) of the Aquitaine Basin, southwest France". '' Scripta Geologica'' 141: http://www.scriptageologica.nl/10/nr141/a01 ;Species brought into synonymy: * (recent) ''Limacina antarctica'' Woodward, 1854:WoRMS (2010). ''Limacina antarctica'' Woodward, 1854. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=509607 on 2011-01-29 synonym of ''Limacina rangii'' f. ''antarctica'' Woodward, 1854: synonym of ''Limacina rangii'' (d'Orbigny, 1834) * ''Limacina balea'' Møller, 1841: synonym of ''Limacina retroversa'' (Fleming, 1823) * ''Limacina contorta'' Sykes, 1905: synonym of ''Limacina trochiformis'' (d'Orbigny, 1834) * ''Limacina crossei'' Pelseneer, 1888: synonym of ''Limacina lesueurii'' (d'Orbigny, 1835) * ''Limacina cucullata'' Gould, 1852: synonym of ''Limacina rangii'' f. ''antarctica'' Woodward, 1854: synonym of ''Limacina rangii'' (d'Orbigny, 1834) * ''Limacina helicialis'' Lamarck, 1819: synonym of ''Limacina helicina'' (Phipps, 1774) * (recent) ''Limacina helicoides'' Jeffreys, 1877 - synonym of '' Thielea helicoides'' (Jeffreys, 1877) * (recent) ''Limacina inflata'' (d'Orbigny, 1836) - Planorbid pteropod. Distribution: circumglobal, Red Sea, Pacific. Length: 1 mm. Description: the shell is flatly twisted, resembling the shell of the cephalopod Nautilus. - synonym: '' Heliconoides inflata'' (d’Orbigny, 1836) * ''Limacina naticoides'' Souleyet, 1852: synonym of ''Limacina trochiformis'' (d'Orbigny, 1834) * ''Limacina pacifica'' Dall, 1871: synonym of ''Limacina helicina pacifica'' Dall, 1871 * ''Limacina scaphoidea'' Gould, 1852: synonym of '' Heliconoides inflatus'' (d'Orbigny, 1834)

References

* Vaught, K.C. (1989). ''A classification of the living Mollusca''. American Malacologists: Melbourne, FL (USA). . XII, 195 pp. * 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 {{Taxonbar, from=Q3202503 Limacinidae Gastropod genera Taxa named by Louis Augustin Guillaume Bosc