''Gorgonocephalus eucnemis'' is a
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of
basket star
The Euryalida are an order of brittle stars, which includes large species with either branching arms (called "basket stars") or long and curling arms (called "snake stars").
Characteristics
Many of the species in this order have characterist ...
in the
class Ophiuroidea
Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomo ...
. It is found in circumpolar marine environments in the Northern Hemisphere. The scientific name for the genus comes from the
Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
, ''gorgós'' meaning "dreadful" and ''cephalus'' meaning "head", and refers to the similarity between these basket stars and the
Gorgon
A Gorgon ( /ˈɡɔːrɡən/; plural: Gorgons, Ancient Greek: Γοργών/Γοργώ ''Gorgṓn/Gorgṓ'') is a creature in Greek mythology. Gorgons occur in the earliest examples of Greek literature. While descriptions of Gorgons vary, the te ...
's head from Greek mythology with its writhing serpents for hair.
[GORGONOCEPHALUS!! Because Weird is what we do!]
EchinoBlog. Retrieved 2012-01-21. The specific name ''eucnemis'' is from the Greek "good" and "boot".
Description
''Gorgonocephalus eucnemis'' has a central disc up to across with five pairs of arms that branch
dichotomously into smaller and smaller subdivisions. Its colour is varying shades of white and beige, often with a darker disc. It has an
endoskeleton
An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue.
Overview
An endoskeleton is a skeleton that is on the ...
of calcified ossicles and is covered in a fleshy layer of skin giving it a rubbery appearance. The arms are covered in tiny hooks and spines which can be used to grip and manipulate food particles.
[''Gorgonocephalus eucnemis'']
The Race Rocks Taxonomy. Retrieved 2012-01-22.
Distribution and habitat
''G. eucnemis'' is found in the Arctic Ocean
The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...
[James A. Grieg, ''Report of the Second Norwegian Arctic Expedition in the "Fram" 1898-1902, No. 13, Vol. 2 ''Echinodermata'' 1907:3, 22ff; specimens found for the first time north and west of ]Baffin Bay
Baffin Bay (Inuktitut: ''Saknirutiak Imanga''; kl, Avannaata Imaa; french: Baie de Baffin), located between Baffin Island and the west coast of Greenland, is defined by the International Hydrographic Organization as a marginal sea of the Ar ...
, in Havne Fjord and northern parts of the Atlantic Ocean as far south as the Faroe Islands
The Faroe Islands ( ), or simply the Faroes ( fo, Føroyar ; da, Færøerne ), are a North Atlantic archipelago, island group and an autonomous territory of the Danish Realm, Kingdom of Denmark.
They are located north-northwest of Scotlan ...
and . It also occurs in the Pacific Ocean from the Bering Sea
The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Amer ...
south to Japan and Laguna Beach, California
Laguna Beach (; ''Laguna'', Spanish for "Lagoon") is a seaside resort city located in southern Orange County, California, in the United States. It is known for its mild year-round climate, scenic coves, environmental preservation efforts, and ...
. It is mostly found in rocky areas with strong currents at depths to , but is most common at depths of . It is also found on mud and sandy seabeds among boulders, sea pen
Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; 35 extant genera, and it is estimated that of 450 described species, around 200 are valid. Sea pens have a cos ...
s, and sea fans
Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different ...
.[''Gorgonocephalus eucnemis'' Muller and Troschel, 1842]
Walla Walla University. Retrieved 2012-01-22.
Biology
It feeds by perching in an elevated position and extending its arms in a net-like fashion perpendicular to the current. The branches and branchlets twist and coil, making it resemble an animated bush.[ It ensnares small ]crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gro ...
s such as the northern krill (''Meganyctiphanes norvegica''), copepod
Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Some species are planktonic (inhabiting sea waters), some are benthic (living on the ocean floor), a number of species have p ...
s, chaetognaths, jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
, and 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 commu ...
that come within reach. Trapped prey becomes the centre of a "knot" where it is immobilised by the secretion of mucus
Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It ...
. Further coiling of the branches brings the food to the mouth which is on the underside of the central disc. Here, the branchlets are passed through a comb-like structure which removes the food particles. There is no anus and any undigested fragments are expelled through the mouth.[
Individual basket stars are either male or female. After spawning, the ]larva
A larva (; plural larvae ) 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.
Th ...
e become part of the plankton
Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...
and disperse with the currents.[
]
Ecology
''G. eucnemis'' is cryptic
Cryptic may refer to:
In science:
* Cryptic species complex, a group of species that are very difficult to distinguish from one another
* Crypsis, the ability of animals to blend in to avoid observation
* Cryptic era, earliest period of the Earth
...
and remains well hidden during the day. It is protected by the toxic nature of the sponges where it lurks, but is sometimes eaten by fish and crabs. It has been observed to return to a specific location regularly.[
It is often found living in association with ]sponge
Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...
s and soft corals in the genus ''Gersemia
''Gersemia'' is a genus of soft corals in the family Nephtheidae. Species in this genus are found in cold temperate and polar seas at depths ranging from to over . The type species is '' Gersemia loricata''.
Characteristics
Colonies of ''Gersem ...
'', hiding under them or in the folds of the sponges during the day and using them as elevated platforms for searching for prey at night.[ In ]Puget Sound
Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected m ...
, juveniles have been found to be living and apparently feeding inside the pharynges of '' Gersemia rubiformis'' polyps, only emerging when sufficiently grown to fend for themselves.[
]
References
{{Taxonbar, from=Q2045008
Gorgonocephalidae
Animals described in 1842