''Crinolina isefiordensis'' is a species of

choanoflagellate The choanoflagellates are a group of free-living unicellular and colonial flagellate eukaryotes considered to be the closest living relatives of the animals. Choanoflagellates are collared flagellates, having a funnel shaped collar of interconne ...

in the family

Acanthoecidae Acanthoecidae is a family of choanoflagellates. Genera ''Acanthocorbis'' - '' Acanthoeca'' - '' Amoenoscopa'' - '' Apheloecion'' - '' Bicosta'' - '' Calliacantha'' - '' Calotheca'' - '' Campyloacantha'' - '' Conion'' - '' Cosmoeca'' - '' Crinoli ...

. It is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus '' Crinolina'' and is named for the first location of its collection, the

Ise Fjord Ise Fjord ( da, Isefjorden) is a deeply branched arm of the sea into the Danish island Zealand. From its relatively narrow entrance from the Kattegat at Hundested and Rørvig, branches of Ise Fjord stretch 35 km inland and divide the northern ...

Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...

Description

''Crinolina isefiordensis'' is a single-celled organism that lives in a skirt-shaped lorica (net-like structure) which is open on both ends. The

protoplast Protoplast (), is a biological term coined by Hanstein in 1880 to refer to the entire cell, excluding the cell wall. Protoplasts can be generated by stripping the cell wall from plant, bacterial, or fungal cells by mechanical, chemical or enzy ...

of the type specimen measured 8

microns The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

by 5 microns and it does not have a

chloroplast A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in ...

. It has a

flagellum A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

between 2-3 times as long as the protoplasts which is ringed by a collar of tentacles inside the lorica. The lorica is even longer, up to 30 microns, and is twice as wide at the base as the neck. The lorica consists of around a dozen costae (filaments that create the exoskeleton) which are roughly straight and connect the costal rings at the base and neck. Each costa is made up of six or seven small strips that are joined. At the neck of the lorica, these costae end in spines that project outwards. The lorica of ''C. isefiordensis'' is highly similar in appearance to that of ''

Diaphanoeca grandis ''Diaphanoeca grandis'' is a species of choanoflagellate in the family Acanthoecidae which is the type species of the genus ''Diaphanoeca''. It is a Unicellular organism, unicellular micro-heterotroph with a large protective Lorica (biology), lor ...

'' in its structure. However, the main difference is that ''C. isefiordensis'' entirely lacks a membrane to connect the costae of the lorica, unlike ''D. grandis''. Additionally, the flagellum of ''C. isefiordensis'' is usually seen curled up in a pig-tail shape, a characteristic unique to the species. There is some minor morphological variance across populations of ''C. isefiordensis''. Most notably, warmer water populations tend to have fewer costae and less apparent spines.

Taxonomy

''Crinolina isefiordensis'' is extremely similar to a Canadian arctic species of choanoflagellate, ''Diaphanoeca aperta''. Because of their similarities, specifically the open rear end of their lorica, the latter species was moved into ''Crinolina'' creating the new combination '' Crinolina aperta''. Later phylogenetic analysis confirmed the close relationship of ''Crinolina'' and ''Diaphanoeca'', but did not merge the genera and suggested that they may be sister to one another.

Distribution and habitat

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

of the species was collected in the winter in the cold waters of

in Denmark. The species has also been collected during the summer at

Limfjord The Limfjord (Danish language, common Danish: ''Limfjorden'' , in north Jutlandish dialect: ''Æ Limfjord'') is a shallow part of the sea, located in Denmark where it has been regarded as a fjord ever since Viking Age, Viking times. However, i ...

. In 2007, ''C. isefiordensis'' was one of the first marine choanoflagellates to be identified off the coast of

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

, and the collected specimens were nearly identical to those from Denmark. More recent studies have proven the species to be nearly

cosmopolitan Cosmopolitan may refer to: Food and drink * Cosmopolitan (cocktail), also known as a "Cosmo" History * Rootless cosmopolitan, a Soviet derogatory epithet during Joseph Stalin's anti-Semitic campaign of 1949–1953 Hotels and resorts * Cosmopoli ...

; it is not found only in low salinity areas like parts of the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and from ...

as well as at extreme latitudes.

References

{{Taxonbar, from=Q120802141 Choanoflagellatea Protists described in 1976 Opisthokont species