Cephalodiscus densus | |
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Species: | C. densus |
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Cephalodiscus densus Andersson, 1907 [1] | |
Cephalodiscus densus is a sessile hemichordate belonging to the order Cephalodiscida. [2] The species is endemic to the Antarctic, being found in the Ross Sea and much of the Antarctic coastline, as well as near the Kerguelen Islands. [3]
Specimens appear bush-like, with fleshy tubules approximately 1 mm in diameter [3] wrapped in a rock shell built of cemented sediment and other foreign material. [4] Individuals live in the upper portion of the shell, and eggs and young are stored in the lower portion, or the colony to which the base attaches. [4] The body is roughly 6 mm long, of which the stalk composes about 4 mm. [3] The preserved flesh appears on average orange in color, with individuals ranging from pale to dark brown. [3] [4]
The largest-known colony of peanut worms is a 2.5-m colony of C. densus. [5]
Hemichordata is a phylum which consists of triploblastic, enterocoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta, and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, Planctosphaera pelagica. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus Rhabdopleura.
Pterobranchia is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 25 known living pterobranch species in three genera, which are Rhabdopleura, Cephalodiscus, and Atubaria. On the other hand, there are several hundred extinct genera, some of which date from the Cambrian Period.
The Gauss expedition of 1901–1903 was the first German expedition to Antarctica. It was led by geologist Erich von Drygalski in the ship Gauss, named after the mathematician and physicist Carl Friedrich Gauss.
Ascoseira is a monotypic genus of seaweed in the brown algae. The single and type species, Ascoseira mirabilis Skottsberg, is a large parenchymatous macroalgae, and is endemic to the Antarctic Ocean. Ascoseira is assigned to its own order. The alga grows in subtidal waters at depths of from 3 to 15 meters.
Conorbela antarctica is a species of sea snail, a marine gastropod mollusk in the family Pseudomelatomidae, the turrids and allies.
Typhlodaphne purissima is a species of sea snail, a marine gastropod mollusk in the family Borsoniidae.
Nacella concinna is a species of sea snail, a true limpet, a marine gastropod mollusk in the family Nacellidae, one of the families of true limpets.
Fuegotrophon pallidus is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.
Liotella crassicostata is a species of sea snail, a marine gastropod mollusk in the family Skeneidae,.
Calliostoma modestulum is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Margarella achilles is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Margarella subantarctica is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Margarella tropidophoroides is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae.
Lissotesta impervia is a species of sea snail, a marine gastropod mollusk, unassigned in the superfamily Seguenzioidea.
Lissotesta notalis is a species of sea snail, a marine gastropod mollusk, unassigned in the superfamily Seguenzioidea.
Cephalodiscus is a genus of hemichordates in the monotypic family Cephalodiscidae of the order Cephalodiscida.
Lorabela pelseneeri is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
Mangelia cingulata is a species of sea snail, a marine gastropod mollusk in the family Mangeliidae.
Pleurotomella bathybia is a species of sea snail, a marine gastropod mollusk in the family Raphitomidae.
Cephalodiscus solidus is a sessile hemichordate belonging to the order Cephalodiscida.