''Limacina rangii'' 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 ...

of swimming

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 ...

in the family

Limacinidae The Limacinidae are a family of small sea snails, pteropods, pelagic marine gastropod mollusks in the clade Thecosomata (sea butterflies).Bouchet, P. (2012). Limacinidae. Accessed through: World Register of Marine Species at http://www.marinespec ...

,Bouchet, P. (2014). Limacina rangii (d'Orbigny, 1834). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=719583 on 2015-01-24 which belong to the group commonly known as

sea butterflies Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified ...

(

Thecosomata Sea butterflies, scientific name Thecosomata (thecosomes, "case / shell-body"), are a taxonomic suborder of small pelagic swimming sea snails. They are holoplanktonic opisthobranch gastropod mollusks. Most Thecosomata have some form of calcified ...

). ''Limacina rangii'' is a

keystone species A keystone species is a species which has a disproportionately large effect on its natural environment relative to its abundance, a concept introduced in 1969 by the zoologist Robert T. Paine. Keystone species play a critical role in maintaini ...

of the

mesozooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...

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 ...

ecosystems. Until 2010 this taxon was known only as ''Limacina helicina antarctica'' or as ''Limacina helicina'' f. ''antarctica''. ''Limacina rangii'' is however now considered to be a separate species from ''

Limacina helicina ''Limacina helicina'' is a species of small swimming planktonic sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies (Thecosomata). ''Limacina helicina'' is a keystone species of mesozooplankton in Ar ...

'', based on

cytochrome c oxidase subunit I Cytochrome c oxidase I (COX1) also known as mitochondrially encoded cytochrome c oxidase I (MT-CO1) is a protein that in humans is encoded by the ''MT-CO1'' gene. In other eukaryotes, the gene is called ''COX1'', ''CO1'', or ''COI''. Cytochrom ...

(COI) gene sequences. Limacina antarctica 2

Distribution

The distribution of ''Limacina rangii'' is circumglobal south of 50°S. This species occurs in the

Weddell Sea The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha ...

and

Ross Sea The Ross Sea is a deep bay of the Southern Ocean in Antarctica, between Victoria Land and Marie Byrd Land and within the Ross Embayment, and is the southernmost sea on Earth. It derives its name from the British explorer James Clark Ross who vi ...

in the

and in

Cumberland Bay Cumberland Bay is a bay, wide at its entrance between Larsen Point and Barff Point, which separates into two extensive arms, Cumberland West Bay and Cumberland East Bay, which recede inland along the northern coast of South Georgia. It ...

South Georgia South Georgia ( es, Isla San Pedro) is an island in the South Atlantic Ocean that is part of the British Overseas Territory of South Georgia and the South Sandwich Islands. It lies around east of the Falkland Islands. Stretching in the east� ...

. and other localities in the

Southern Ocean The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-small ...

Description

''Limacina rangii'' has a sinistral and very thin shell. The shell thickness is approximately 2–9 μm. There are ribs on the surface of the shell. There are differences in the shell structure between ''Limacina rangii'' and ''

''. The width of the shell is 0.5–6 mm.

Ecology

''Limacina rangii'' is a

holoplankton Holoplankton are organisms that are plankton, planktic (they live in the water column and cannot swim against a current) for their entire life cycle. Holoplankton can be contrasted with meroplankton, which are planktic organisms that spend part of ...

ic species. It is very abundant in the Southern Ocean, with up to 2681 individuals per m³. This species is abundant in the

, Antarctica. It is sometimes even more abundant than

krill Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in n ...

. ''Limacina rangii'' feeds mainly on

phytoplankton Phytoplankton () are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words (), meaning 'plant', and (), meaning 'wanderer' or 'drifter'. Ph ...

and also on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

, but less so. It catches its prey using

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...

webs. This snail is a

primary consumer A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

and directly depends on phytoplankton. When the phytoplankton is reduced, the population of ''Limacina rangii'' is also reduced, and it can even disappear as happened in

McMurdo Sound McMurdo Sound is a sound in Antarctica. It is the southernmost navigable body of water in the world, and is about from the South Pole. Captain James Clark Ross discovered the sound in February 1841, and named it after Lt. Archibald McMurdo o ...

in the summer of 2000–2001. It is considered an

indicator species A bioindicator is any species (an indicator species) or group of species whose function, population, or status can reveal the qualitative status of the environment. The most common indicator species are animals. For example, copepods and other sma ...

of the health of the ecosystem. Under different conditions in McMurdo Sound there can be over 300 individuals per m³, which is over 20% of the

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

Fecal pellet Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

s of ''Limacina rangii'' and its quantity have been firstly described by Manno et al. (2010). Fecal pellets are oval, greenish brown and with

peritrophic membrane The peritrophic matrix (from the prefix ''peri-'', meaning around, and ''-trophic'', referring to nutrition(food)) or peritrophic membrane is a semi-permeable, non-cellular structure which surrounds the food bolus in an organism's midgut. Although ...

. A size of a single pellet varies from 103 μm (286600 μm³) to 120 μm (440,610 μm³). A single ''Limacina rangii'' produces about 6-11 pellets daily. Population of ''Limacina rangii'' in the studied area in the Ross Sea produced from about 71,000 pellets per square meter per year to about 362,000 pellets per square meter per year. Fecal pellets of ''Limacina rangii'' has contributed to about 19% of flux of

organic carbon Total organic carbon (TOC) is the amount of carbon found in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment. TOC may also refer to the amount of organic c ...

. Fecal pellets of ''Limacina rangii'' together with dead ''Limacina rangii'' can cover up to 72% (estimation) of organic

carbon flux The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component ...

to the deep water. ''Limacina rangii'' probably affect

carbon cycle The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and Earth's atmosphere, atmosphere of the Earth. Carbon is the main component of biological compounds as well as ...

, resources of

and

dimethyl sulfide Dimethyl sulfide (DMS) or methylthiomethane is an organosulfur compound with the formula (CH3)2S. Dimethyl sulfide is a flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cook ...

(emission by phytoplankton), that may have impact on the Earth's

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...

. Many predators depend on ''Limacina rangii'' as their food source: * The gastropod ''

Clione antarctica ''Clione antarctica'' is a species of "sea angel", a sea slug, a pelagic marine gastropod mollusk in the family Clionidae, the "sea angels". Distribution The distribution of ''Clione antarctica'' is within the Southern Hemisphere, in the p ...

'' feeds only on ''Limacina rangii''. There is a

coevolution In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well ...

ary relationship between this specialized predator and its prey; their life cycles are parallel. * The medusae '' Solmundella bitentaculata'' and ''

Diplulmaris antarctica ''Diplulmaris antarctica'' is a species of Antarctic jellyfish in the family Ulmaridae. Description This species grows up to in diameter. ''Diplulmaris antarctica'' has 16 - 48 laterally compressed, white tentacles and a white frontal lobe. I ...

Ceratoscopelus warmingii (Warming's lantern fish)

* Fish in the family Myctophidae heavily depend on ''Limacina rangii''. ''Limacina'' are food for a number of myctophid fishes in the Southern Ocean: '' Electrona antarctica'', ''

Electrona paucirastra ''Electrona paucirastra'', the belted lanternfish, is a lanternfish found around the globe in the southern hemisphere between 35° S and 48° S. It grows to a length of SL. It is a mesopelagic The mesopelagic zone (Greek μέσον, middle) ...

'', ''

Electrona subaspera ''Electrona subaspera'', also known as the rough lanternfish, is a marine, mesopelagic fish.Hulley, P.A., 1990. Myctophidae. p. 146-178. In O. Gon and P.C. Heemstra (eds.) Fishes of the Southern Ocean. J.L.B. Smith Institute of Ichthyology, Graha ...

'', ''

Metelectrona herwigi ''Metelectrona'' is a genus of lanternfishes. Species There are currently three recognized species in this genus: * ''Metelectrona ahlstromi'' Robert Lester Wisner, Wisner, 1963 * ''Metelectrona herwigi'' P. Alexander Hulley, Hulley, 1981 (Herwi ...

'', ''

Protomyctophum normani ''Protomyctophum normani'' is a species of lanternfish Lanternfishes (or myctophids, from the Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family Myctophidae. One of two families in ...

'', '' Diaphus taaningi'', '' Diaphus hudsoni'', '' Gymnoscopelus nicholsi'', ''

Ceratoscopelus warmingii ''Ceratoscopelus'' is a genus of lanternfish. Species There are currently three recognized species in this genus: * ''Ceratoscopelus maderensis'' ( R. T. Lowe, 1839) (Madeira lanternfish) * ''Ceratoscopelus townsendi ''Ceratoscopelus'' is a ...

'' and '' Symbolophorus boops''. * Also notothenioid fish (family

Nototheniidae : ''In some scientific literature, the term "cod icefish" is used to identify members of this family. This should not be confused with the term "icefish," which refers to the "white-blooded" fishes of the family Channichthyidae. See Icefish (disam ...

) heavily depend on ''Limacina rangii'' as food. For example, fishes: ''

Trematomus newnesi ''Trematomus'' is a genus of marine ray-finned fishes, belonging to the family Nototheniidae, the notothens or cod icefishes. These fishes occur in the Southern Ocean. Taxonomy ''Trematomus'' was first described as a genus in 1902 by the Belgian ...

'', ''

Trematomus bernacchii The emerald rockcod (''Trematomus bernacchii''), also known as the emerald notothen is a species of marine ray-finned fish belonging to the family Nototheniidae, the notothens or cod icefishes. It is native to the Southern Ocean where it is a c ...

'', ''

Trematomus hansoni ''Trematomus'' is a genus of marine ray-finned fishes, belonging to the family Nototheniidae, the notothens or cod icefishes. These fishes occur in the Southern Ocean. Taxonomy ''Trematomus'' was first described as a genus in 1902 by the Belgian ...

'', '' Trematomus centronotus'' and '' Pagothenia borchgrevink''. *

Whales Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

heavily depend on this species

References

* Hunt B., Strugnell J., Bednarsek N., Linse K., Nelson R.J., Pakhomov E., Seibel B., Steinke D. & Würzberg L. (2010). ''Poles apart: The "bipolar" pteropod species Limacina helicina is genetically distinct between the Arctic and Antarctic Oceans.'' PLoS One 5(3):e9835

External links

Map of distribution of ''Limacina antarctica''
at Marine Species Identification Portal. {{Taxonbar, from=Q13762958 Limacinidae Gastropods described in 1854