Limacina
Encyclopedia
Limacina is a genus
of swimming predatory sea snail
s commonly known as sea butterflies
in the family Limacinidae
. This genus contains some of the world's most abundant gastropod species.
Etymological meaning of the generic name Limacina is "snail-like".
These little snails are pelagic, and they are marine
gastropod mollusks. They swim by flapping their parapodia, and that flapping action is the reason why they were given the common name
sea butterflies.
The sea butterflies are part of the order Thecosomata. The sea angels, which look a little similar and are also pelagic swimming snails, are in a different order, the Gymnosomata. Both of these orders are still sometimes called "pteropods"; the sea butterflies of the order Thecosomata have a shell, while the sea angels in the order Gymnosomata lack a shell.
. In Arctic and temperate waters, the diameter of the shell does not exceed 15 mm. In warmer waters, the diameter varies from 1 to 3 mm.
but also bacteria, small crustacean
s, gastropod larva
e, dinoflagellate
s and diatom
s. They entangle their planktonic food through a mucous web that can be up to 5 cm wide, many times larger than themselves. This web is eaten as soon as there is enough food entangled and then a new one is soon deployed. This net also provides them additional buoyancy. If disturbed, they dump the net and flap away.
There is a posterior footlobe with cilia, and a pair of lateral footlobes. They transport food, collected by the mucous web, to the mouth.
When they migrate to the surface, they may do so in unbelievably huge numbers. These aggregations usually attract their predators, the sea angels of the genus Clione (family Clionidae
, suborder Gymnosomata). They are also on the menu of baleen whale
s, chunk salmon, pink salmon, herring and certain seabird
s.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of swimming predatory sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
s commonly known as sea butterflies
Sea butterfly
Sea butterflies, also known as Thecosomata or flapping snails, are a taxonomic suborder of small pelagic swimming sea snails. These are holoplanktonic opisthobranch gastropod mollusks in the informal group Opisthobranchia. They include some of the world's most abundant gastropod species.This group...
in the family Limacinidae
Limacinidae
Limacinidae is a family of small sea snails, pteropods, pelagic marine gastropod mollusks in the clade Thecosomata .-Genera:Genera within the family Limacinidae include:...
. This genus contains some of the world's most abundant gastropod species.
Etymological meaning of the generic name Limacina is "snail-like".
These little snails are pelagic, and they are marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusks. They swim by flapping their parapodia, and that flapping action is the reason why they were given the common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
sea butterflies.
The sea butterflies are part of the order Thecosomata. The sea angels, which look a little similar and are also pelagic swimming snails, are in a different order, the Gymnosomata. Both of these orders are still sometimes called "pteropods"; the sea butterflies of the order Thecosomata have a shell, while the sea angels in the order Gymnosomata lack a shell.
Shell description
The shells of these sea butterflies are well developed, sinistrally coiled, turret-like and unpigmented. Shell sizes and thicknesses vary within Limacina, but they are still large enough for the animal to fit into. There is also an operculumOperculum (gastropod)
The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...
. In Arctic and temperate waters, the diameter of the shell does not exceed 15 mm. In warmer waters, the diameter varies from 1 to 3 mm.
Description of the soft parts
There are two large winglike parapodia, derived from foot tissue. The sea butterflies are continually flapping these wings to prevent sinking, because the shell gives them some negative buoyancy. During the daytime, they tend to move to deeper waters, but no lower than 100 m.Life habits
The sea butterflies have a peculiar way of feeding. They used to be regarded as passive feeders, but in reality they are active hunters, feeding mostly on planktonPlankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
but also bacteria, small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, gastropod larva
Larva
A larva 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...
e, dinoflagellate
Dinoflagellate
The dinoflagellates are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well. Their populations are distributed depending on temperature, salinity, or depth...
s and diatom
Diatom
Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...
s. They entangle their planktonic food through a mucous web that can be up to 5 cm wide, many times larger than themselves. This web is eaten as soon as there is enough food entangled and then a new one is soon deployed. This net also provides them additional buoyancy. If disturbed, they dump the net and flap away.
There is a posterior footlobe with cilia, and a pair of lateral footlobes. They transport food, collected by the mucous web, to the mouth.
When they migrate to the surface, they may do so in unbelievably huge numbers. These aggregations usually attract their predators, the sea angels of the genus Clione (family Clionidae
Clionidae
Clionidae is a family of sea angels, which are a group of pelagic marine gastropods.They are shaped a little like angels, and have flapping "wings", hence their common name. They are gelatinous, mostly transparent pteropods, and they only have shells in their embryonic stage...
, suborder Gymnosomata). They are also on the menu of baleen whale
Baleen whale
The Baleen whales, also called whalebone whales or great whales, form the Mysticeti, one of two suborders of the Cetacea . Baleen whales are characterized by having baleen plates for filtering food from water, rather than having teeth. This distinguishes them from the other suborder of cetaceans,...
s, chunk salmon, pink salmon, herring and certain seabird
Seabird
Seabirds are birds that have 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 environmental problems and feeding niches have resulted in similar adaptations...
s.
Species
Species within the genus Limacina include:- (recent) Limacina antarcticaLimacina antarcticaLimacina antarctica is a species of swimming sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies ....
Woodward, 1854 - (recent) Limacina bulimoides (d'OrbignyAlcide d'OrbignyAlcide Charles Victor Marie Dessalines d'Orbigny was a French naturalist who made major contributions in many areas, including zoology , palaeontology, geology, archaeology and anthropology....
, 1836) - Bulimoid pteropod. Distribution: Red Sea, Pacific. Length: 1.2 mm. - † Limacina erasmiana Janssen, 2010
- † Limacina gormani (Curry, 1982)
- † Limacina guersi Janssen, 2010
- (recent) Limacina helicinaLimacina helicinaLimacina helicina is a species of small swimming predatory sea snail in the family Limacinidae, which belong to the group commonly known as sea butterflies ....
(Phipps, 1774) - Helicid pteropod. Type species. - (recent) Limacina helicoides Jeffreys, 1877 - synonym:(?) Thielea procera Strebel, 1908
- (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 NautilusNautilusNautilus is the common name of marine creatures of cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina. It comprises six living species in two genera, the type of which is the genus Nautilus...
. - synonym: Heliconoides inflata (d’Orbigny, 1836) - (recent) Limacina lesueurii (d'Orbigny, 1836) - Distribution: North America, Western Atlantic.
- † Limacina pygmaea (Lamarck, 1805)
- (recent) Limacina retroversaLimacina retroversaLimacina retroversa is a species of swimming predatory sea snail in the family Limacinidae, that belong to the group commonly known as sea butterflies .- Ecology :...
(Fleming, 1823) - Retrovert pteropod. Distribution: North America, Western Atlantic, Arctic Ocean. - † 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, 2010