page_title: Limacina helicina
section_title: Description
hierarchical_section_title: Limacina helicina / Description
caption_attribution_description: English: Drawing of part of Limacina helicina from ventral view shows parapodia, anterior lobe of the parapodia, lower part of the foot, folding on the ventral side of the foot.
context_page_description: 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.
  Limacina helicina is a keystone species of mesozooplankton in Arctic pelagic ecosystems.
  The first written record of this species was by Friderich Martens from Spitsbergen in 1675. Limacina helicina was also observed during a 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.
  Limacina helicina is the type species of the genus Limacina.
  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.
context_section_description: Limacina helicina has wing-like parapodia which evolved from the original gastropod foot (as is the case in all other pteropods).
  In this species, the color of the soft parts is dark purple or violet, with paler pellucid (translucent) parapodia.
  The shell is sinistral, subglobose, subdiscoidal, hyaline and very thin. The spire is depressed but it can be considered rather high in comparison of other Limacina species. The shell has 5-6 transversally striated whorls. The suture is distinct. The last whorl is large and with very obscure keel next to its umbilicus. The shell has a wide umbilicus. The aperture is higher than it is wide.
  The width of the shell is 5–10 mm or up to 13 mm. The height of the shell is up to 6 mm (when maximum width was 8 mm).
  Adult specimens in the genus Limacina have usually lost the operculum.
  The radula consist of 10 rows. Each row consist of one central tooth and two lateral teeth. The Digestive system also includes an esophagus, gizzard sac and gut.
caption: 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.
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