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''Limacina helicina'' is a [[keystone species]] of [[mesozooplankton]] in [[Arctic]] [[pelagic]] ecosystems.<ref name="Sato-Okoshi 2010"/><ref name="Comeau 2009"/><ref name="Comeau 2010"/>
''Limacina helicina'' is a [[keystone species]] of [[mesozooplankton]] in [[Arctic]] [[pelagic]] ecosystems.<ref name="Sato-Okoshi 2010"/><ref name="Comeau 2009"/><ref name="Comeau 2010"/>


The first written record of this species was by [[Friderich Martens]] from [[Spitsbergen]] in 1675.<ref>{{de icon}} [[Friderich Martens|Martens F.]] (1675). [http://resolver.sub.uni-goettingen.de/purl?PPN48644435X ''Spitzbergische oder Groenlandische Reise Beschreibung gethan im Jahr 1671'']. Schultzen, Hamburg. page 110 <nowiki>http://dfg-viewer.de/en/version-20-deprecated/?set[image]=118&set[zoom]=default&set[debug]=0&set[double]=0&set[mets]=http%3A%2F%2Fgdz.sub.uni-goettingen.de%2Fmets_export.php%3FPPN%3DPPN48644435X</nowiki><br/> Plate Q, figure e <nowiki>http://dfg-viewer.de/en/version-20-deprecated/?set[image]=171&set[mets]=http%3A%2F%2Fgdz.sub.uni-goettingen.de%2Fmets_export.php%3FPPN%3DPPN48644435X&set[zoom]=default&set[debug]=0&set[double]=0&set[style]=</nowiki></ref><ref name="Gilmer 1991"/> ''Limacina helicina'' was also observed during an 1773 expedition to the [[Arctic]] led by [[Constantine John Phipps]] on the ships [[HMS Racehorse (1757)|HMS ''Racehorse'']] and on [[HMS Carcass (1759)|HMS ''Carcass'']] and the species was [[Species description|described]] one year later, in 1774.<ref name="Phipps 1774"/>
The first written record of this species was by [[Friderich Martens]] from [[Spitsbergen]] in 1675.<ref>{{de icon}} [[Friderich Martens|Martens F.]] (1675). [http://resolver.sub.uni-goettingen.de/purl?PPN48644435X ''Spitzbergische oder Groenlandische Reise Beschreibung gethan im Jahr 1671'']. Schultzen, Hamburg. page 110</ref><ref name="Gilmer 1991"/> ''Limacina helicina'' was also observed during an 1773 expedition to the [[Arctic]] led by [[Constantine John Phipps]] on the ships [[HMS Racehorse (1757)|HMS ''Racehorse'']] and on [[HMS Carcass (1759)|HMS ''Carcass'']] and the species was [[Species description|described]] one year later, in 1774.<ref name="Phipps 1774"/>


''Limacina helicina'' is the [[type species]] of the genus ''Limacina''.<ref>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</ref>
''Limacina helicina'' is the [[type species]] of the genus ''Limacina''.<ref>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</ref>
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''Limacina helicina'' has been recognised as a species complex comprising two sub-species and at least five [[Form (zoology)|forms]].<ref name="Hunt 2010"/> In addition, the taxonomic category “forma” has been applied to designate at least three morphotypes of ''Limacina helicina helicina'' (''acuta'', ''helicina'' and ''pacifica'') and two morphotypes of ''Limacina helicina antarctica'' (''antarctica'' and ''rangi'').<ref name="Hunt 2010"/> It is also known as ''Limacina helicina rangii'' (d'Orbigny, 1835).<ref name="WoRMS 2011"/> These forms typically have different geographical ranges, but it remains unclear as to whether forms represent morphological responses to different environmental conditions or are indeed taxonomically distinct, and if the latter, their level of taxonomic separation.<ref name="Hunt 2010"/>
''Limacina helicina'' has been recognised as a species complex comprising two sub-species and at least five [[Form (zoology)|forms]].<ref name="Hunt 2010"/> In addition, the taxonomic category “forma” has been applied to designate at least three morphotypes of ''Limacina helicina helicina'' (''acuta'', ''helicina'' and ''pacifica'') and two morphotypes of ''Limacina helicina antarctica'' (''antarctica'' and ''rangi'').<ref name="Hunt 2010"/> It is also known as ''Limacina helicina rangii'' (d'Orbigny, 1835).<ref name="WoRMS 2011"/> These forms typically have different geographical ranges, but it remains unclear as to whether forms represent morphological responses to different environmental conditions or are indeed taxonomically distinct, and if the latter, their level of taxonomic separation.<ref name="Hunt 2010"/>


However, at the species level the geographical distribution is considered to be bipolar, as it occurs in both the Arctic and [[Antarctic]] oceans.<ref name="Hunt 2010"/> Remigio and Hebert (2003)<ref>Remigio E. A. & Hebert P. D. N. (2003). "Testing the utility of partial COI sequences for phylogenetic estimates of gastropod relationships". ''[[Molecular Phylogenetics and Evolution]]'' '''29'''(3): 641-647. [[doi:10.1016/S1055-7903(03)00140-4]].</ref> provided initial evidence for the genetic separation of ''Limacina helicina helicina'' and ''Limacina helicina antarctica''.<ref name="Hunt 2010"/> Hunt et al. (2010)<ref name="Hunt 2010"/> have quantified [[genetic distance]] within these taxa. Hunt 2010 found a 33.56% difference in [[cytochrome c oxidase subunit I]] (COI) gene sequences between the "''Limacina helicina''" which were collected from the Arctic and the Antarctic oceans.<ref name="Hunt 2010"/> This degree of separation is sufficient for ordinal level taxonomic separation in other organisms, and provides strong evidence for the Arctic and Antarctic populations of ''Limacina helicina'' differing at least at the [[species]] level.<ref name="Hunt 2010"/> Subspecies ''Limacina helicina antarctica'' Woodward, 1854 can be considered as a separate species ''[[Limacina antarctica]]'' Woodward, 1854.<ref name="WoRMS 2011"/> A [[Bayesian inference in phylogeny|conservative divergence time estimate]] of 31 Ma (95% HPD interval 12–53 Ma) for Arctic and Antarctic taxa, indicates that they have undergone rapid independent [[evolution]] since the establishment of cold water provinces in the [[early Oligocene]].<ref name="Hunt 2010"/> Also there is different structure of the shell between ''Limacina helicina'' and ''Limacina antarctica''.<ref name="Sato-Okoshi 2010">Sato-Okoshi W., Okoshi K., Sasaki H. & Akiha F. (2010). "Shell structure of two polar pelagic molluscs, Arctic ''Limacina helicina'' and Antarctic ''Limacina helicina antarctica'' forma ''antarctica''". ''Polar Biology'' '''33'''(11): 1577-1583. [[doi:10.1007/s00300-010-0849-1]].</ref>
However, at the species level the geographical distribution is considered to be bipolar, as it occurs in both the Arctic and [[Antarctic]] oceans.<ref name="Hunt 2010"/> Remigio and Hebert (2003)<ref>{{Cite doi|10.1016/S1055-7903(03)00140-4|noedit}}</ref> provided initial evidence for the genetic separation of ''Limacina helicina helicina'' and ''Limacina helicina antarctica''.<ref name="Hunt 2010"/> Hunt et al. (2010)<ref name="Hunt 2010"/> have quantified [[genetic distance]] within these taxa. Hunt 2010 found a 33.56% difference in [[cytochrome c oxidase subunit I]] (COI) gene sequences between the "''Limacina helicina''" which were collected from the Arctic and the Antarctic oceans.<ref name="Hunt 2010"/> This degree of separation is sufficient for ordinal level taxonomic separation in other organisms, and provides strong evidence for the Arctic and Antarctic populations of ''Limacina helicina'' differing at least at the [[species]] level.<ref name="Hunt 2010"/> Subspecies ''Limacina helicina antarctica'' Woodward, 1854 can be considered as a separate species ''[[Limacina antarctica]]'' Woodward, 1854.<ref name="WoRMS 2011"/> A [[Bayesian inference in phylogeny|conservative divergence time estimate]] of 31 Ma (95% HPD interval 12–53 Ma) for Arctic and Antarctic taxa, indicates that they have undergone rapid independent [[evolution]] since the establishment of cold water provinces in the [[early Oligocene]].<ref name="Hunt 2010"/> Also there is different structure of the shell between ''Limacina helicina'' and ''Limacina antarctica''.<ref name="Sato-Okoshi 2010">{{Cite doi|10.1007/s00300-010-0849-1|noedit}}</ref>


== Distribution ==
== Distribution ==
The [[type locality (biology)|type locality]] of ''Limacina helicina'' is "Arctic seas".<ref name="Phipps 1774"/> ''Limacina helicina'' is the only thecosome pteropod in Arctic waters.<ref name="Comeau 2010"/>
The [[type locality (biology)|type locality]] of ''Limacina helicina'' is "Arctic seas".<ref name="Phipps 1774"/> ''Limacina helicina'' is the only thecosome pteropod in Arctic waters.<ref name="Comeau 2010"/>


The distribution of ''Limacina helicina'' is [[arctic]] and [[subarctic]] ([[Subarctic climate|subpolar]]–[[Polar region|polar]])<ref>Orr J. C., Fabry V. J., Aumont O., Bopp L., Doney S. C. et al. (2005). "Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms". ''[[Nature (journal)|Nature]]'' '''437''': 681-686. [[doi:10.1038/nature04095]]. [http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf PDF]. ([http://hdl.handle.net/1912/370 author's draft]).</ref> especially in the [[Arctic Ocean]] and countries include:
The distribution of ''Limacina helicina'' is [[arctic]] and [[subarctic]] ([[Subarctic climate|subpolar]]–[[Polar region|polar]])<ref>{{Cite doi|10.1038/nature04095|noedit}} [http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf PDF]. ([http://hdl.handle.net/1912/370 author's draft]).</ref> especially in the [[Arctic Ocean]] and countries include:
* Northern Atlantic Ocean between 50–60 °N,<ref name="Spoel 1972"/> [[Norwegian Sea]],<ref name="Spoel 1972"/> [[Faroe Islands]],<ref name="Spoel 1972"/> [[Spitsbergen]],<ref name="Comeau 2009"/><ref name="Spoel 1972"/> North of [[Iceland]]<ref name="Spoel 1972"/>
* Northern Atlantic Ocean between 50–60 °N,<ref name="Spoel 1972"/> [[Norwegian Sea]],<ref name="Spoel 1972"/> [[Faroe Islands]],<ref name="Spoel 1972"/> [[Spitsbergen]],<ref name="Comeau 2009"/><ref name="Spoel 1972"/> North of [[Iceland]]<ref name="Spoel 1972"/>
* Greenland:<ref name="WoRMS 2011"/> [[Denmark Strait]]<ref name="Spoel 1972"/> and [[Davis Strait]]<ref name="Spoel 1972"/>
* Greenland:<ref name="WoRMS 2011"/> [[Denmark Strait]]<ref name="Spoel 1972"/> and [[Davis Strait]]<ref name="Spoel 1972"/>
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The width of the shell is 5–10&nbsp;mm<ref name="Comeau 2009"/> or up to 13&nbsp;mm.<ref name="Gilmer 1991"/> The height of the shell is up to 6&nbsp;mm (when maximum width was 8&nbsp;mm).<ref name="Spoel 1972">Spoel S. van der (1972). [http://www.ices.dk/products/fiche/Plankton/SHEET140-142.PDF "Pteropoda Thecosomata"]. ''Zooplankton'', Conseil International Pour L’Exploration de la Mer, sheet 140-142.</ref>
The width of the shell is 5–10&nbsp;mm<ref name="Comeau 2009"/> or up to 13&nbsp;mm.<ref name="Gilmer 1991"/> The height of the shell is up to 6&nbsp;mm (when maximum width was 8&nbsp;mm).<ref name="Spoel 1972">Spoel S. van der (1972). [http://www.ices.dk/products/fiche/Plankton/SHEET140-142.PDF "Pteropoda Thecosomata"]. ''Zooplankton'', Conseil International Pour L’Exploration de la Mer, sheet 140-142.</ref>
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The maximum recorded [[gastropod shell|shell]] length of ''Limacina helicina helicina'' is 8 mm.<ref name="Welch 2010">Welch J. J. (2010). "The “Island Rule” and Deep-Sea Gastropods: Re-Examining the Evidence". ''[[PLoS ONE]]'' '''5'''(1): e8776. [[doi:10.1371/journal.pone.0008776]].</ref>
The maximum recorded [[gastropod shell|shell]] length of ''Limacina helicina helicina'' is 8 mm.<ref name="Welch 2010">{{Cite doi|10.1371/journal.pone.0008776|noedit}}</ref>
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Already [[Constantine John Phipps]] mentioned its "innumerable quantities" in arctic seas in 1774.<ref name="Phipps 1774"/> ''Limacina helicina'' is a major component of the polar [[zooplankton]].<ref name="Hunt 2010"/> It can comprise >50% of total zooplankton abundance (number of individuals per unit volume).<ref name="Hunt 2010"/>
Already [[Constantine John Phipps]] mentioned its "innumerable quantities" in arctic seas in 1774.<ref name="Phipps 1774"/> ''Limacina helicina'' is a major component of the polar [[zooplankton]].<ref name="Hunt 2010"/> It can comprise >50% of total zooplankton abundance (number of individuals per unit volume).<ref name="Hunt 2010"/>


Species of the clade [[Thecosomata]] produce a fragile external [[calcium carbonate]] shell, which could serve as a [[Sailing ballast|ballast]] enabling large [[vertical migration]]s and as a protection against predators.<ref name="Comeau 2010"/> The [[aragonitic]] composition of the shell makes it very sensitive to dissolution.<ref name="Comeau 2010"/> [[Aragonite]] is a metastable form of calcium carbonate and it is more soluble in seawater than [[calcite]].<ref name="Comeau 2009"/> Because of its highly soluble<ref name="Comeau 2010"/> aragonite shell and polar distribution, ''Limacina helicina'' may be one of the first organisms affected by [[ocean acidification]], and it is therefore a key [[indicator species]] of this process.<ref name="Hunt 2010"/> As a key indicator of the acidification process, and a major component of polar ecosystems, ''Limacina helicina'' has become a focus for acidification research.<ref name="Hunt 2010"/> Based on labolatory experiments, they are able to precipitate calcium carbonate at low aragonite saturation state.<ref name="Comeau 2010"/> ''Limacina helicina'' seems to be relatively more resilient to elevated concentration of [[carbon dioxide]] (CO<sub>2</sub>) than other aragonitic organisms such as [[coral]]s.<ref name="Comeau 2010"/> Labolatory experiments results support the current concern for the future of Arctic pteropods, as the production of their shell appears to be very sensitive to decreased [[pH]].<ref name="Comeau 2009"/><ref name="Comeau 2010"/> A decline of pteropod populations would likely cause dramatic changes to various pelagic ecosystems.<ref name="Comeau 2009"/><ref name="Comeau 2010"/> Shelled pteropods also play a geochemical role in [[carbon cycle]] in the oceans, as they contribute to the export of [[calcium carbonate]] and can represent a major component of the carbon transport to the [[deep ocean]].<ref name="Comeau 2009">Comeau S., Gorsky G., Jeffree R., Teyssie J.-L. & Gattuso J.-P. (2009). "Impact of ocean acidification on a key Arctic pelagic mollusc (''Limacina helicina'')". ''[[Biogeosciences]]'' '''6''': 1877-1882. [[doi:10.5194/bg-6-1877-2009]].</ref><ref name="Comeau 2010"/><ref name="Hunt 2010"/>
Species of the clade [[Thecosomata]] produce a fragile external [[calcium carbonate]] shell, which could serve as a [[Sailing ballast|ballast]] enabling large [[vertical migration]]s and as a protection against predators.<ref name="Comeau 2010"/> The [[aragonitic]] composition of the shell makes it very sensitive to dissolution.<ref name="Comeau 2010"/> [[Aragonite]] is a metastable form of calcium carbonate and it is more soluble in seawater than [[calcite]].<ref name="Comeau 2009"/> Because of its highly soluble<ref name="Comeau 2010"/> aragonite shell and polar distribution, ''Limacina helicina'' may be one of the first organisms affected by [[ocean acidification]], and it is therefore a key [[indicator species]] of this process.<ref name="Hunt 2010"/> As a key indicator of the acidification process, and a major component of polar ecosystems, ''Limacina helicina'' has become a focus for acidification research.<ref name="Hunt 2010"/> Based on labolatory experiments, they are able to precipitate calcium carbonate at low aragonite saturation state.<ref name="Comeau 2010"/> ''Limacina helicina'' seems to be relatively more resilient to elevated concentration of [[carbon dioxide]] (CO<sub>2</sub>) than other aragonitic organisms such as [[coral]]s.<ref name="Comeau 2010"/> Labolatory experiments results support the current concern for the future of Arctic pteropods, as the production of their shell appears to be very sensitive to decreased [[pH]].<ref name="Comeau 2009"/><ref name="Comeau 2010"/> A decline of pteropod populations would likely cause dramatic changes to various pelagic ecosystems.<ref name="Comeau 2009"/><ref name="Comeau 2010"/> Shelled pteropods also play a geochemical role in [[carbon cycle]] in the oceans, as they contribute to the export of [[calcium carbonate]] and can represent a major component of the carbon transport to the [[deep ocean]].<ref name="Comeau 2009">{{Cite doi|10.5194/bg-6-1877-2009|noedit}}</ref><ref name="Comeau 2010"/><ref name="Hunt 2010"/>


=== Feeding habits ===
=== Feeding habits ===
They produce large mucus webs to filter-feed on phytoplankton but also small zooplankton.<ref name="Comeau 2010"/> They eat the web with the captured prey and then re-reproduce a web net.<ref name="Hopcroft 2009"/> The web is large and spherical<ref name="Gilmer 1986">Gilmer R. W. & Harbison G. R. (1986). "Morphology and field behavior of pteropod molluscs: feeding methods in the families Cavoliniidae, Limacinidae and Peraclididae (Gastropoda: Thecosomata)". ''Marine Biology'' '''91'''(1): 47-57. [[doi:10.1007/BF00397570]].</ref> and it is difficult to see during the day because of [[diffuse reflection]].<ref name="Gilmer 1991"/> Webs are easier to see at night.<ref name="Gilmer 1991"/> ''Limacina helicina'' is easily disturbed (like all other [[Thecosomata]]); when disturbed, it retracts into its shell and destroys its web.<ref name="Gilmer 1991"/> Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> have assumed, that ''Limacina helicina'' feeds while motionless (without actively swimming).<ref name="Gilmer 1991"/> Its web enables them [[neutral buoyancy]] or allow them slow sinking only.<ref name="Gilmer 1986"/>
They produce large mucus webs to filter-feed on phytoplankton but also small zooplankton.<ref name="Comeau 2010"/> They eat the web with the captured prey and then re-reproduce a web net.<ref name="Hopcroft 2009"/> The web is large and spherical<ref name="Gilmer 1986">{{Cite doi|10.1007/BF00397570|noedit}}</ref> and it is difficult to see during the day because of [[diffuse reflection]].<ref name="Gilmer 1991"/> Webs are easier to see at night.<ref name="Gilmer 1991"/> ''Limacina helicina'' is easily disturbed (like all other [[Thecosomata]]); when disturbed, it retracts into its shell and destroys its web.<ref name="Gilmer 1991"/> Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> have assumed, that ''Limacina helicina'' feeds while motionless (without actively swimming).<ref name="Gilmer 1991"/> Its web enables them [[neutral buoyancy]] or allow them slow sinking only.<ref name="Gilmer 1986"/>


''Limacina helicina'' it plays a significant ecological role as a [[phytoplankton]] grazer.<ref name="Hunt 2010"/> ''Limacina helicina'' is obligate ciliary feeder.<ref name="Kobayashi 1974"/> Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> hypothetized, that ''Limacina helicina'' are "web trappers", who are also chemically attracting its motile prey.<ref name="Gilmer 1991"/>
''Limacina helicina'' it plays a significant ecological role as a [[phytoplankton]] grazer.<ref name="Hunt 2010"/> ''Limacina helicina'' is obligate ciliary feeder.<ref name="Kobayashi 1974"/> Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> hypothetized, that ''Limacina helicina'' are "web trappers", who are also chemically attracting its motile prey.<ref name="Gilmer 1991"/>


Major parts of the food of ''Limacina helicina'' include [[tintinnid]] (Tintinnida), small crustaceans - [[copepod]]s (Copepoda) and juvenile specimen of its own species ([[Cannibalism (zoology)|cannibalism]]).<ref name="Gilmer 1991">Gilmer R. W. & Harbison G. R. (1991). "Diet of ''Limacina helicina'' (Gastropoda: Thecosomata) in Arctic waters in midsummer". ''Marine Ecology Progress Series'' '''77''': 125-134. [http://www.int-res.com/articles/meps/77/m077p125.pdf PDF].</ref> Danish zoologist [[Johan Erik Vesti Boas]] reported [[diatom]]s (Bacillariophyceae), [[dinoflagellate]]s (Dinoflagellata) and tintinnids in the [[digestive system of gastropods|digestive system]] of ''Limacina helicina'' in 1888 already.<ref>{{da icon}} [[Johan Erik Vesti Boas|Boas J. E. V.]] (1888). "Spolia Atlantica. Bidrag til Pteropodernes. Morfologi og Systematik samt til Kundskaben om deres geografiski Udbredelse". ''Det Kongelige Danske videnskabernes selskabs skrifter''. København, serie 6, number 4: 1-231. Page [http://www.archive.org/stream/detkongeligedans64kong#page/32/mode/2up 33], [http://www.archive.org/stream/detkongeligedans64kong#page/40/mode/2up 40]-43. [http://www.archive.org/stream/detkongeligedans64kong#page/n268/mode/1up Plate 5], figure 69-70.</ref> Diatoms and dinoflagellates appear to pass the digestive system of adults largely intact.<ref name="Gannefors 2005">Gannefors C., Böer M., Kattner G., Graeve M., Eiane K., Gulliksen B., Hop H. & Falk-Petersen S. (2005). "The Arctic sea butterfly ''Limacina helicina'': lipids and life strategy". ''Marine Biology'' '''147''': 169-177. [[doi:10.1007/s00227-004-1544-y]].</ref><ref name="Gilmer 1991"/> [[Fecal pellet]]s of ''Limacina helicina'' contains small cells, dinoflagellates and diatoms as main largely intact food items and also few small fragments of tintinnids, ''Limacina'' and copepods.<ref name="Gilmer 1991"/> All experiments performed on ''Limacina helicina'' in the laboratory were done on starved specimens, because they do not feed in unnatural conditions.<ref name="Gilmer 1991"/>
Major parts of the food of ''Limacina helicina'' include [[tintinnid]] (Tintinnida), small crustaceans - [[copepod]]s (Copepoda) and juvenile specimen of its own species ([[Cannibalism (zoology)|cannibalism]]).<ref name="Gilmer 1991">Gilmer R. W. & Harbison G. R. (1991). "Diet of ''Limacina helicina'' (Gastropoda: Thecosomata) in Arctic waters in midsummer". ''Marine Ecology Progress Series'' '''77''': 125-134. [http://www.int-res.com/articles/meps/77/m077p125.pdf PDF].</ref> Danish zoologist [[Johan Erik Vesti Boas]] reported [[diatom]]s (Bacillariophyceae), [[dinoflagellate]]s (Dinoflagellata) and tintinnids in the [[digestive system of gastropods|digestive system]] of ''Limacina helicina'' in 1888 already.<ref>{{da icon}} [[Johan Erik Vesti Boas|Boas J. E. V.]] (1888). "Spolia Atlantica. Bidrag til Pteropodernes. Morfologi og Systematik samt til Kundskaben om deres geografiski Udbredelse". ''Det Kongelige Danske videnskabernes selskabs skrifter''. København, serie 6, number 4: 1-231. Page [http://www.archive.org/stream/detkongeligedans64kong#page/32/mode/2up 33], [http://www.archive.org/stream/detkongeligedans64kong#page/40/mode/2up 40]-43. [http://www.archive.org/stream/detkongeligedans64kong#page/n268/mode/1up Plate 5], figure 69-70.</ref> Diatoms and dinoflagellates appear to pass the digestive system of adults largely intact.<ref name="Gannefors 2005">{{Cite doi|10.1007/s00227-004-1544-y|noedit}}</ref><ref name="Gilmer 1991"/> [[Fecal pellet]]s of ''Limacina helicina'' contains small cells, dinoflagellates and diatoms as main largely intact food items and also few small fragments of tintinnids, ''Limacina'' and copepods.<ref name="Gilmer 1991"/> All experiments performed on ''Limacina helicina'' in the laboratory were done on starved specimens, because they do not feed in unnatural conditions.<ref name="Gilmer 1991"/>


Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> also suggested that smaller specimens may be [[herbivore]]s feeding preferentially on [[phytoplankton]] and [[protozoan]]s and that larger specimens became omnivores.<ref name="Gilmer 1991"/>
Gilmer & Harbison (1991)<ref name="Gilmer 1991"/> also suggested that smaller specimens may be [[herbivore]]s feeding preferentially on [[phytoplankton]] and [[protozoan]]s and that larger specimens became omnivores.<ref name="Gilmer 1991"/>
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The size of the [[veliger]] larvae is about 0.15&nbsp;mm.<ref name="Hopcroft 2009">Hopcroft R. (created 31 January 2009). [http://www.arcodiv.org/watercolumn/pteropod/Limacina_helicina.html "Sea Butterfly: ''Limacina helicina'' (Phipps, 1774)"]. Arctic Ocean biodiversity, accessed 30 January 2011.</ref> When animals reached 0.7&nbsp;mm in size, [[gonad]]s have been detected in them.<ref name="Kobayashi 1974"/> Fully mature individuals are 0.8&nbsp;mm in size.<ref name="Kobayashi 1974"/>
The size of the [[veliger]] larvae is about 0.15&nbsp;mm.<ref name="Hopcroft 2009">Hopcroft R. (created 31 January 2009). [http://www.arcodiv.org/watercolumn/pteropod/Limacina_helicina.html "Sea Butterfly: ''Limacina helicina'' (Phipps, 1774)"]. Arctic Ocean biodiversity, accessed 30 January 2011.</ref> When animals reached 0.7&nbsp;mm in size, [[gonad]]s have been detected in them.<ref name="Kobayashi 1974"/> Fully mature individuals are 0.8&nbsp;mm in size.<ref name="Kobayashi 1974"/>


The life cycle of ''Limacina helicina'' lasts about 1 year<ref name="Gannefors 2005"/> or 1.5–2 years.<ref name="Kobayashi 1974">Kobayashi H. A. (1974). "Growth cycle and related vertical distribution of the thecosomatous pteropod ''Spiratella'' “''Limacina''” ''helicina'' in the central Arctic Ocean". ''Marine Biology'' '''26'''(4): 295-301. [[doi:10.1007/BF00391513]].</ref>
The life cycle of ''Limacina helicina'' lasts about 1 year<ref name="Gannefors 2005"/> or 1.5–2 years.<ref name="Kobayashi 1974">{{Cite doi|10.1007/BF00391513|noedit}}</ref>


=== Predators ===
=== Predators ===
''Limacina helicina'' plays an important role in the marine [[food web]] as a major dietary component for predators such as large [[zooplankton]], [[herring]] ''Clupea'' sp.,<ref name="Wing">Wing B. (not dated). [http://www.afsc.noaa.gov/Quarterly/jas2005/divrptsABL1.htm "Auke Bay Laboratory (ABL). Ocean Carrying Capacity Program. Unusual Observations of Fish and Invertebrates From the Gulf of Alaska, 2004-05"]. accessed 29 January 2011.</ref> [[chum salmon]] ''Oncorhynchus keta'',<ref name="Wing"/> [[pink salmon]] ''Oncorhynchus gorbuscha'',<ref name="Wing"/> [[rorqual]] [[whale]]s,<ref name="Wing"/><ref name="species-identification.org">[http://species-identification.org/species.php?species_group=pelagic_molluscs&id=280&menuentry=groepen "''Limacina helicina helicina helicina''"]. Marine Species Identification Portal, accessed 8 February 2011.</ref> ''[[Phoca hispida]]''<ref name="species-identification.org"/> and other [[Pinniped|seals]]<ref name="species-identification.org"/> and birds.<ref name="Comeau 2010"/>
''Limacina helicina'' plays an important role in the marine [[food web]] as a major dietary component for predators such as large [[zooplankton]], [[herring]] ''Clupea'' sp.,<ref name="Wing">Wing B. (not dated). [http://www.afsc.noaa.gov/Quarterly/jas2005/divrptsABL1.htm "Auke Bay Laboratory (ABL). Ocean Carrying Capacity Program. Unusual Observations of Fish and Invertebrates From the Gulf of Alaska, 2004-05"]. accessed 29 January 2011.</ref> [[chum salmon]] ''Oncorhynchus keta'',<ref name="Wing"/> [[pink salmon]] ''Oncorhynchus gorbuscha'',<ref name="Wing"/> [[rorqual]] [[whale]]s,<ref name="Wing"/><ref name="species-identification.org">[http://species-identification.org/species.php?species_group=pelagic_molluscs&id=280&menuentry=groepen "''Limacina helicina helicina helicina''"]. Marine Species Identification Portal, accessed 8 February 2011.</ref> ''[[Phoca hispida]]''<ref name="species-identification.org"/> and other [[Pinniped|seals]]<ref name="species-identification.org"/> and birds.<ref name="Comeau 2010"/>


The pteropod ''[[Clione limacina]]'' feeds only on the genus ''Limacina'': on ''Limacina helicina'' and on ''[[Limacina retroversa]]''.<ref name="Lalli 1989">Lalli C. M. & Gilmer R. W. (1989). ''Pelagic Snails. The biology of holoplanktonic gastropod molluscs.'' Stanford University Press: Stanford, California. [http://books.google.com/books?id=yIAfwz5cxPMC&lpg=PP1&dq=Pelagic%20Snails%3A%20The%20Biology%20of%20Holoplanktonic%20Gastropod%20Molluscs&hl=cs&pg=PA185#v=onepage&q=Clione%20limacina&f=false page 185], [http://books.google.com/books?id=yIAfwz5cxPMC&lpg=PP1&dq=Pelagic%20Snails%3A%20The%20Biology%20of%20Holoplanktonic%20Gastropod%20Molluscs&hl=cs&pg=PA188#v=onepage&q=Clione%20limacina&f=false 188].</ref><ref name="Böer 2005">Böer M., Gannefors C., Kattner G., Graeve M., Hop H. & Falk-Petersen S. (2005). "The Arctic pteropod ''Clione limacina'': seasonal lipid dynamics and life-strategy". ''Marine Biology'' '''147'''(3): 707-717. [[doi:10.1007/s00227-005-1607-8]].</ref> Also the pteropod ''[[Paedoclione doliiformis]]'' feeds on those two species only, but solely on juveniles with shells smaller than 1&nbsp;mm.<ref name="Lalli 1989"/>
The pteropod ''[[Clione limacina]]'' feeds only on the genus ''Limacina'': on ''Limacina helicina'' and on ''[[Limacina retroversa]]''.<ref name="Lalli 1989">Lalli C. M. & Gilmer R. W. (1989). ''Pelagic Snails. The biology of holoplanktonic gastropod molluscs.'' Stanford University Press: Stanford, California. [http://books.google.com/books?id=yIAfwz5cxPMC&lpg=PP1&dq=Pelagic%20Snails%3A%20The%20Biology%20of%20Holoplanktonic%20Gastropod%20Molluscs&hl=cs&pg=PA185#v=onepage&q=Clione%20limacina&f=false page 185], [http://books.google.com/books?id=yIAfwz5cxPMC&lpg=PP1&dq=Pelagic%20Snails%3A%20The%20Biology%20of%20Holoplanktonic%20Gastropod%20Molluscs&hl=cs&pg=PA188#v=onepage&q=Clione%20limacina&f=false 188].</ref><ref name="Böer 2005">{{Cite doi|10.1007/s00227-005-1607-8
|noedit}}</ref> Also the pteropod ''[[Paedoclione doliiformis]]'' feeds on those two species only, but solely on juveniles with shells smaller than 1&nbsp;mm.<ref name="Lalli 1989"/>


== See also ==
== See also ==
Line 133: Line 134:


== References ==
== References ==
This article incorporates CC-BY-2.5 text from the reference <ref name="Comeau 2010">Comeau S., Jeffree R., Teyssié J.-L. & Gattuso J.-P. (2010). "Response of the Arctic Pteropod ''Limacina helicina'' to Projected Future Environmental Conditions". ''[[PLoS ONE]]'' '''5'''(6): e11362. [[doi:10.1371/journal.pone.0011362]].</ref><ref name="Hunt 2010">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. [[doi:10.1371/journal.pone.0009835]].</ref> and public domain text from the reference <ref name="Tryon 1873">[[George Washington Tryon|Tryon G. W.]] (1873). ''American marine conchology: or, Descriptions of the shells of the Atlantic coast of the United States from Maine to Florida''. Philadelphia. [http://www.archive.org/stream/americanmarineco01tryo#page/120/mode/2up page 121]-122. [http://www.archive.org/stream/americanmarineco01tryo#page/n242/mode/1up plate 14], figure 253.</ref>
This article incorporates CC-BY-2.5 text from the reference <ref name="Comeau 2010">{{Cite doi|10.1371/journal.pone.0011362|noedit}}</ref><ref name="Hunt 2010">{{Cite doi|10.1371/journal.pone.0009835|noedit}}</ref> and public domain text from the reference <ref name="Tryon 1873">[[George Washington Tryon|Tryon G. W.]] (1873). ''American marine conchology: or, Descriptions of the shells of the Atlantic coast of the United States from Maine to Florida''. Philadelphia. [http://www.archive.org/stream/americanmarineco01tryo#page/120/mode/2up page 121]-122. [http://www.archive.org/stream/americanmarineco01tryo#page/n242/mode/1up plate 14], figure 253.</ref>
{{Reflist}}
{{Reflist}}


== Further reading ==
== Further reading ==
* {{Cite pmid|2991789|noedit}}
* {{ru icon}} Arshavskiĭ Iu. I., Orlovskiĭ G. N. & Panchin Iu V. (1985). "[Generation of locomotor rhythms in ''Limacina helicina'']". ''Neirofiziologiia'' '''17'''(3): 397-400. {{PMID|2991789}}
* {{Cite doi|10.1007/s003000000190|noedit}}
* Falk-Petersen S., Sargent J. R., Kwasniewski S., Gulliksen B. & Millar R.-M. (2001). "Lipids and fatty acids in ''Clione limacina'' and ''Limacina helicina'' in Svalbard waters and the Arctic Ocean: trophic implications". ''Polar Biology'' '''24'''(3): 163-170. [[doi:10.1007/s003000000190]].
* {{Cite doi|10.1111/j.1469-7998.1978.tb03359.x|noedit}}
* Lalli C. M. & Wells F. E. (1978). "Reproduction in the genus ''Limacina'' (Opisthobranchia, Thecosomata)". ''[[Journal of Zoology]]'' '''186'''(1): 95-108. [[doi:10.1111/j.1469-7998.1978.tb03359.x]].


== External links ==
== External links ==

Revision as of 18:21, 21 May 2012

Limacina helicina
A live individual of Limacina helicina
A live individual of Limacina helicina
Scientific classification
Kingdom:
Animalia
Subkingdom:
Metazoa
Phylum:
Mollusca
Class:
Gastropoda
(unranked):
clade Heterobranchia

clade Euthyneura
clade Euopisthobranchia

clade Thecosomata
Superfamily:
Cavolinioidea
Family:
Limacinidae
Genus:
Limacina
Species:
L. helicina
Binomial name
Limacina helicina
(Phipps, 1774)[1]
Synonyms[6]

Limacina helicina is a species of small swimming predatory sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies (Thecosomata).[7][8]

Limacina helicina is a keystone species of mesozooplankton in Arctic pelagic ecosystems.[9][10][11]

The first written record of this species was by Friderich Martens from Spitsbergen in 1675.[12][13] Limacina helicina was also observed during an 1773 expedition to the Arctic led by Constantine John Phipps on the ships HMS Racehorse and on HMS Carcass and the species was described one year later, in 1774.[1]

Limacina helicina is the type species of the genus Limacina.[14]

In contrast to the traditional view, it was shown in 2010 that the distribution of this species is not bipolar; Arctic and Antarctic individuals belong to two genetically distinct species: Limacina helicina in the Arctic, and Limacina antarctica in the Antarctic.[11][15]

Subspecies

  • Limacina helicina helicina (Phipps, 1774)[16]
  • Limacina helicina acuta Van Der Spoel, 1967[17]
  • Limacina helicina ochotensis Shkoldina, 1999[16]
  • Limacina helicina pacifica Dall, 1871[18]

Limacina helicina has been recognised as a species complex comprising two sub-species and at least five forms.[15] In addition, the taxonomic category “forma” has been applied to designate at least three morphotypes of Limacina helicina helicina (acuta, helicina and pacifica) and two morphotypes of Limacina helicina antarctica (antarctica and rangi).[15] It is also known as Limacina helicina rangii (d'Orbigny, 1835).[16] These forms typically have different geographical ranges, but it remains unclear as to whether forms represent morphological responses to different environmental conditions or are indeed taxonomically distinct, and if the latter, their level of taxonomic separation.[15]

However, at the species level the geographical distribution is considered to be bipolar, as it occurs in both the Arctic and Antarctic oceans.[15] Remigio and Hebert (2003)[19] provided initial evidence for the genetic separation of Limacina helicina helicina and Limacina helicina antarctica.[15] Hunt et al. (2010)[15] have quantified genetic distance within these taxa. Hunt 2010 found a 33.56% difference in cytochrome c oxidase subunit I (COI) gene sequences between the "Limacina helicina" which were collected from the Arctic and the Antarctic oceans.[15] This degree of separation is sufficient for ordinal level taxonomic separation in other organisms, and provides strong evidence for the Arctic and Antarctic populations of Limacina helicina differing at least at the species level.[15] Subspecies Limacina helicina antarctica Woodward, 1854 can be considered as a separate species Limacina antarctica Woodward, 1854.[16] A conservative divergence time estimate of 31 Ma (95% HPD interval 12–53 Ma) for Arctic and Antarctic taxa, indicates that they have undergone rapid independent evolution since the establishment of cold water provinces in the early Oligocene.[15] Also there is different structure of the shell between Limacina helicina and Limacina antarctica.[9]

Distribution

The type locality of Limacina helicina is "Arctic seas".[1] Limacina helicina is the only thecosome pteropod in Arctic waters.[11]

The distribution of Limacina helicina is arctic and subarctic (subpolar–polar)[20] especially in the Arctic Ocean and countries include:

Description

Drawing of part of Limacina helicina from ventral view shows parapodia, anterior lobe of the parapodia, lower part of the foot and foldings on the ventral side of the foot.
Detailed drawing of the same ventral view.

Limacina helicina has wing-like parapodia which evolved from the original gastropod foot (as is the case in all other pteropods).[11]

In this species, the color of the soft parts is dark purple or violet, with paler pellucid (translucent) parapodia.[24]

Dorsal view.
Left lateral view.
Frontal view.

The shell is sinistral, subglobose, subdiscoidal,[25] hyaline and very thin. The spire is depressed[25][26] but it can be considered rather high in comparison of other Limacina species.[21] The shell has 5-6 transversally striated whorls.[21][26] The suture is distinct.[21] The last whorl is large and with very obscure keel next to its umbilicus.[21][25] The shell has a wide umbilicus.[21] The aperture is higher than it is wide.[21]

The width of the shell is 5–10 mm[10] or up to 13 mm.[13] The height of the shell is up to 6 mm (when maximum width was 8 mm).[21]

Apical view.
Apertural view.
Umbilical view.
Drawing of operculum of Limacina helicina.

Adult specimens in the genus Limacina have usually lost the operculum.[21]

The radula consist of 10 rows.[24] Each row consist of one central tooth and two lateral teeth.[24] The Digestive system also includes an esophagus, gizzard sac and gut.[13]

Drawing of the whole radula. Magnified 60×.
Detail of radula showing 3 rows of teeth. Magnified 190×.

Ecology

Habitat

Live Limacina helicina. The white rectangle shows the shell opening, the area where Comeau et al. (2009)[10] studied the effect of ocean acidification.

Pteropods are strict pelagic mollusks that are highly adapted to life in the open ocean.[11] They are actively swimming in the water. Limacina helicina is a holoplanktonic species. Habitat of Limacina helicina is upper epipelagic and glacial.[16] It lives in temperatures from -0.4 °C to +4.0 °C or rarely up to 7 °C.[27]

Vertical distribution is affected by the size and also by other factors.[28] Limacina helicina of the size from 0.2 to 0.4 mm lives mainly in depths from 0 m to 50 m.[28] Larger pteropods lives from 0 m to 150 m.[28] For example Gilmer & Harbison (1991)[13] have found larger specimen of Limacina helicina to occur mainly in depths 5–25 m with abundance up to 2.5 adults in m3.[13] They do not occur much in upper 4 m probably because of turbulence.[13]

Already Constantine John Phipps mentioned its "innumerable quantities" in arctic seas in 1774.[1] Limacina helicina is a major component of the polar zooplankton.[15] It can comprise >50% of total zooplankton abundance (number of individuals per unit volume).[15]

Species of the clade Thecosomata produce a fragile external calcium carbonate shell, which could serve as a ballast enabling large vertical migrations and as a protection against predators.[11] The aragonitic composition of the shell makes it very sensitive to dissolution.[11] Aragonite is a metastable form of calcium carbonate and it is more soluble in seawater than calcite.[10] Because of its highly soluble[11] aragonite shell and polar distribution, Limacina helicina may be one of the first organisms affected by ocean acidification, and it is therefore a key indicator species of this process.[15] As a key indicator of the acidification process, and a major component of polar ecosystems, Limacina helicina has become a focus for acidification research.[15] Based on labolatory experiments, they are able to precipitate calcium carbonate at low aragonite saturation state.[11] Limacina helicina seems to be relatively more resilient to elevated concentration of carbon dioxide (CO2) than other aragonitic organisms such as corals.[11] Labolatory experiments results support the current concern for the future of Arctic pteropods, as the production of their shell appears to be very sensitive to decreased pH.[10][11] A decline of pteropod populations would likely cause dramatic changes to various pelagic ecosystems.[10][11] Shelled pteropods also play a geochemical role in carbon cycle in the oceans, as they contribute to the export of calcium carbonate and can represent a major component of the carbon transport to the deep ocean.[10][11][15]

Feeding habits

They produce large mucus webs to filter-feed on phytoplankton but also small zooplankton.[11] They eat the web with the captured prey and then re-reproduce a web net.[26] The web is large and spherical[29] and it is difficult to see during the day because of diffuse reflection.[13] Webs are easier to see at night.[13] Limacina helicina is easily disturbed (like all other Thecosomata); when disturbed, it retracts into its shell and destroys its web.[13] Gilmer & Harbison (1991)[13] have assumed, that Limacina helicina feeds while motionless (without actively swimming).[13] Its web enables them neutral buoyancy or allow them slow sinking only.[29]

Limacina helicina it plays a significant ecological role as a phytoplankton grazer.[15] Limacina helicina is obligate ciliary feeder.[28] Gilmer & Harbison (1991)[13] hypothetized, that Limacina helicina are "web trappers", who are also chemically attracting its motile prey.[13]

Major parts of the food of Limacina helicina include tintinnid (Tintinnida), small crustaceans - copepods (Copepoda) and juvenile specimen of its own species (cannibalism).[13] Danish zoologist Johan Erik Vesti Boas reported diatoms (Bacillariophyceae), dinoflagellates (Dinoflagellata) and tintinnids in the digestive system of Limacina helicina in 1888 already.[30] Diatoms and dinoflagellates appear to pass the digestive system of adults largely intact.[8][13] Fecal pellets of Limacina helicina contains small cells, dinoflagellates and diatoms as main largely intact food items and also few small fragments of tintinnids, Limacina and copepods.[13] All experiments performed on Limacina helicina in the laboratory were done on starved specimens, because they do not feed in unnatural conditions.[13]

Gilmer & Harbison (1991)[13] also suggested that smaller specimens may be herbivores feeding preferentially on phytoplankton and protozoans and that larger specimens became omnivores.[13]

Life cycle

Limacina helicina is a protandric hermaphrodite.[8][28] Males are smaller, at sizes of 4–5 mm[8] and then they change to females, which are larger than 5 mm.[8] Sperm is transferred by spermatophores during copulation.[31] They lay eggs in ribbon-like clusters[8] mainly in summer, but also a little in winter.[28]

The size of the veliger larvae is about 0.15 mm.[26] When animals reached 0.7 mm in size, gonads have been detected in them.[28] Fully mature individuals are 0.8 mm in size.[28]

The life cycle of Limacina helicina lasts about 1 year[8] or 1.5–2 years.[28]

Predators

Limacina helicina plays an important role in the marine food web as a major dietary component for predators such as large zooplankton, herring Clupea sp.,[22] chum salmon Oncorhynchus keta,[22] pink salmon Oncorhynchus gorbuscha,[22] rorqual whales,[22][27] Phoca hispida[27] and other seals[27] and birds.[11]

The pteropod Clione limacina feeds only on the genus Limacina: on Limacina helicina and on Limacina retroversa.[31][32] Also the pteropod Paedoclione doliiformis feeds on those two species only, but solely on juveniles with shells smaller than 1 mm.[31]

See also

  • What appears to be "Limacina helicina" occurring in Antarctica is in fact a separate species, Limacina antarctica. All pre-2010 works refer to this Antarctic taxon as Limacina helicina.

References

This article incorporates CC-BY-2.5 text from the reference [11][15] and public domain text from the reference [25]

  1. ^ a b c d Phipps C. J. (1774). A Voyage towards the North Pole undertaken by His Majesty's Command 1773. J. Nourse, London, viii + 253 pp. Page 195.
  2. ^ Template:La icon Fabricius O. (1780). Fauna Groenlandica systematice sistens animalis Groenlandiae occidentalis hactenus indagata. Hafniae et Lipsiae. J. G. Rothe pp. XVI + 452 + 1 pl. Page 386-388.
  3. ^ Template:Fr icon Lamarck J.-B. (1819). Histoire naturelle des animaux sans vertèbres. Paris. Volume 6. page 291.
  4. ^ Template:Fr icon de Blainville H. M. D. (1824). In: Cuvier F. (ed.). (1804-1845). Dictionnaire des Sciences Naturelles dans lequel on traite méthodiquement des différens êtres de la nature. Levrault, Strasbourg & Paris, and Le Normant, Paris, 32: page 284.
  5. ^ a b Template:De icon Meisenheimer J. (1906). Die Pteropoden der deutschen Sud-polar Expedition 1901-1903. In: Deutsche Sudpolar-Expedition 1901-1903. 9 (Zool.), 1(2): 92-152, pl. 5-7. page 96-98. Plate 5, figure 1 a-b, 3.
  6. ^ "Limacina helicina (Phipps, 1774)". CLEMAM, accessed 29 January 2011.
  7. ^ Bouchet P. & Gofas S. (2011). Limacina helicina (Phipps, 1774). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=140223 on 2011-02-07
  8. ^ a b c d e f g Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s00227-004-1544-y, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s00227-004-1544-y instead.
  9. ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s00300-010-0849-1, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s00300-010-0849-1 instead.
  10. ^ a b c d e f g h Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.5194/bg-6-1877-2009, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.5194/bg-6-1877-2009 instead.
  11. ^ a b c d e f g h i j k l m n o p Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1371/journal.pone.0011362, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1371/journal.pone.0011362 instead.
  12. ^ Template:De icon Martens F. (1675). Spitzbergische oder Groenlandische Reise Beschreibung gethan im Jahr 1671. Schultzen, Hamburg. page 110
  13. ^ a b c d e f g h i j k l m n o p q r s Gilmer R. W. & Harbison G. R. (1991). "Diet of Limacina helicina (Gastropoda: Thecosomata) in Arctic waters in midsummer". Marine Ecology Progress Series 77: 125-134. PDF.
  14. ^ 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
  15. ^ a b c d e f g h i j k l m n o p q Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1371/journal.pone.0009835, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1371/journal.pone.0009835 instead.
  16. ^ a b c d e f g Bouchet, P.; Gofas, S. (2011). Limacina helicina (Phipps, 1774). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=140223 on 2011-01-29
  17. ^ Spoel S. van der (1967). "Euthecosomata, a group with remarkable developmental stages (Gastropoda, Pteropoda)". J. Noorduyn and Zn, Gorinchem, 375 pp.
  18. ^ Dall W. H. (1871). "Descriptions of sixty new forms of mollusks from the west coast of North America and the north Pacific Ocean, with notes on others already described". American Journal of Conchology 7(2): 93-160, plates 13-16. Pages 138-139.
  19. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/S1055-7903(03)00140-4, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/S1055-7903(03)00140-4 instead.
  20. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1038/nature04095, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1038/nature04095 instead. PDF. (author's draft).
  21. ^ a b c d e f g h i j k l m n o p Spoel S. van der (1972). "Pteropoda Thecosomata". Zooplankton, Conseil International Pour L’Exploration de la Mer, sheet 140-142.
  22. ^ a b c d e Wing B. (not dated). "Auke Bay Laboratory (ABL). Ocean Carrying Capacity Program. Unusual Observations of Fish and Invertebrates From the Gulf of Alaska, 2004-05". accessed 29 January 2011.
  23. ^ Hermans C. O. & Satterlie R. A. (1992). "Fast-Strike Feeding Behaviour in a Pteropod Mollusk, Clione limacina Phipps". The Biological bulletin, Marine Biological Laboratory, 182: 1-7.
  24. ^ a b c Template:La icon Template:No icon Sars G. O. (1878). Bidrag til kundskaben om norges arktiske fauna. I. Mollusca regonis arcticae Norwegiae. Oversigt over de i norges arktiske region forekommende bløddyr. Christiania, Brøgger. pages 328-329, Plate 29, figure 1. Plate 16, figure 17.
  25. ^ a b c d Tryon G. W. (1873). American marine conchology: or, Descriptions of the shells of the Atlantic coast of the United States from Maine to Florida. Philadelphia. page 121-122. plate 14, figure 253.
  26. ^ a b c d Hopcroft R. (created 31 January 2009). "Sea Butterfly: Limacina helicina (Phipps, 1774)". Arctic Ocean biodiversity, accessed 30 January 2011.
  27. ^ a b c d "Limacina helicina helicina helicina". Marine Species Identification Portal, accessed 8 February 2011.
  28. ^ a b c d e f g h i Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/BF00391513, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/BF00391513 instead.
  29. ^ a b Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/BF00397570, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/BF00397570 instead.
  30. ^ Template:Da icon Boas J. E. V. (1888). "Spolia Atlantica. Bidrag til Pteropodernes. Morfologi og Systematik samt til Kundskaben om deres geografiski Udbredelse". Det Kongelige Danske videnskabernes selskabs skrifter. København, serie 6, number 4: 1-231. Page 33, 40-43. Plate 5, figure 69-70.
  31. ^ a b c Lalli C. M. & Gilmer R. W. (1989). Pelagic Snails. The biology of holoplanktonic gastropod molluscs. Stanford University Press: Stanford, California. page 185, 188.
  32. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s00227-005-1607-8 , please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s00227-005-1607-8 instead.

Further reading

  • Attention: This template ({{cite pmid}}) is deprecated. To cite the publication identified by PMID 2991789, please use {{cite journal}} with |pmid=2991789 instead.
  • Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/s003000000190, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/s003000000190 instead.
  • Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1111/j.1469-7998.1978.tb03359.x, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1111/j.1469-7998.1978.tb03359.x instead.

External links

Wikimedia Commons has media related to Limacina helicina.
  • distribution map at Marine Species Identification Portal
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