Echinoderm
Marine animals with five-pointed radial symmetry and unique water vascular system.
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Echinoderms are marine animals with a five-pointed radial symmetry as adults, though their larvae are bilaterally symmetrical.[1][2] They include starfish, brittle stars, sea urchins, sand dollars, sea cucumbers, and sea lilies.[1] These animals are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone.[1]
Quick Facts
- Type genus
- Echinus
Facts from the source article.
Key facts and history
Five extant classes are generally recognized: Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea, and Crinoidea.[1] They possess a unique water vascular system, a network of fluid-filled canals modified from the coelom.[1] This system functions in gas exchange, feeding, sensory reception, and locomotion.[1] Jacob Theodor Klein, in 1734, first used the term Echinodermata, but he applied it solely to echinoids.[2]
Currently, roughly 10,500 species of echinoderms are alive, and around 13,000 species are known only from fossils.[3] Within the dermis, echinoderms possess a skeleton derived from mesoderm, which is made of calcite plates referred to as ossicles.[1] A common ability among echinoderms is strong regeneration; they frequently autotomize and then regrow arms and internal organs.[4] The sexes are separate in nearly all echinoderm species, though hermaphroditism occurs in some.[2]
What the cited sources add
The article further reports that in 1955, Libbie Hyman attributed the name to "Bruguière, 1791"[2] This attribution is listed by the Integrated Taxonomic Information System, though some workers believe the rules should result in attributing "Klein, 1778"[1] Francis Arthur Bather, in his 1900 treatise, proposed the name "Echinoderma" for the phylum; however, that name is now used for a fungus.[5]
References
- Wikipedia, "Echinoderm" (CC BY-SA 4.0), which cites: ; (original not read by us) en.wikipedia.org
- Wikipedia, "Echinoderm" (CC BY-SA 4.0) en.wikipedia.org
- Wikipedia, "Echinoderm" (CC BY-SA 4.0), which cites: "Echinoderms"; ; (original not read by us) en.wikipedia.org
- Wikipedia, "Echinoderm" (CC BY-SA 4.0), which cites: ; ; ; ; ; ; ; (original not read by us) en.wikipedia.org
- Wikipedia, "Echinoderm" (CC BY-SA 4.0), which cites: ; ; ; (original not read by us) en.wikipedia.org
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Echinoderm (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Echinoderm (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
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