marine
Marine is an adjective meaning of or pertaining to the sea or ocean.
Marine or marines may refer to:
Ocean
* Maritime (disambiguation)
* Marine art
* Marine biology
* Marine debris
* Marine habitats
* Marine life
* Marine pollution
Military
* ...
Notocrinidae
Notocrinidae is a monotypic family of crinoids, the only genus being ''Notocrinus'', which contains two species, both endemic to the seas around Antarctica.
Description
Members of this family have five arms which subdivide near the base giving t ...
. It is found in deep water in the Southern Ocean around the coasts of Antarctica and adjacent islands. A
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 ...
sometimes parasitizes it.
Description
''Notocrinus virilis'' is a robust, stalkless crinoid with ten arms (five arms, each subdivided into two) up to long. There are five deep radial pits on the centro-dorsal axis of the disc, forming a "radial star". There are fewer than fifty cirri at the base of the calyx. The pinnules that extend from either side of the arms are relatively short and are circular in cross section. The gonads are on the lower pinnules and there are brood pouches between these pinnules and the arms. This crinoid is dark red in colour, a colour that is already becoming apparent in the late stage, stalked larvae.
Distribution and habitat
Endemic to the Southern Ocean waters around Antarctica, ''N. virilis'' probably has a circumpolar distribution. It is known from the
Antarctic Peninsula
The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctic ...
, the
South Orkney Islands
The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic PeninsulaEnderby Land, the
Adélie Land
Adélie Land (french: Terre Adélie, ) is a claimed territory on the continent of Antarctica. It stretches from a portion of the Southern Ocean coastline all the way inland to the South Pole. France has administered it as one of five districts ...
, the
Balleny Islands
The Balleny Islands () are a series of uninhabited islands in the Southern Ocean extending from 66°15' to 67°35'S and 162°30' to 165°00'E. The group extends for about in a northwest-southeast direction. The islands are heavily glaciated an ...
cirri
Giovanni Battista Cirri (1 October 1724 – 11 June 1808) was an Italian cellist and composer in the 18th century.
Biography
Cirri was born in Forlì in the Emilia-Romagna Region of Italy. He had his first musical training with his brother ...
and can also use them to climb to an elevated position in which to feed. Like all crinoids, it is a
filter feeder
Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...
, spreading its arms and pinnules widely to catch plankton and small particles of
detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
from the water flowing past. The sexes are separate, and females brood their young in their brood pouches; the larvae may reach in length before being expelled from the pouch and falling to the sea bed, to which they will anchor themselves.
In early deep sea research, organisms were dredged up from the sea bed but during the trawl, any link between one species and another was often lost. More recently, it has been discovered that ''N. virilis'' often has a gastropod mollusc, '' Bathycrinicola tumidula'', attached to it, the first time a snail from this family has been associated with a crinoid. Research in 2007 by Schiaparelli showed that ''B. tumidula'' is parasitic on ''N. virilis'', and no other Antarctic crinoids have been found to act as
hosts
A host is a person responsible for guests at an event or for providing hospitality during it.
Host may also refer to:
Places
*Host, Pennsylvania, a village in Berks County
People
*Jim Host (born 1937), American businessman
*Michel Host ( ...
to the mollusc. Some of the parasitic snails were found to have inserted their proboscises between ossicles near the base of the crown while others were attached between calcareous plates on the arms.