Cephalodiscus
Cephalodiscus | ||||||||||||
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Cephalodiscus dodecalophus |
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Systematics | ||||||||||||
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Scientific name of the order | ||||||||||||
Cephalodiscoidea | ||||||||||||
Beklemishev , 1951 | ||||||||||||
Scientific name of the family | ||||||||||||
Cephalodiscidae | ||||||||||||
Harmer , 1905 | ||||||||||||
Scientific name of the genus | ||||||||||||
Cephalodiscus | ||||||||||||
M'Intosh , 1882 |
Cephalodiscus ( Gr . "Kephale" = head, + "diskos" = disk) is a genus of marine invertebrates from the class of wing gills (Pterobranchia). They live at depths of 100 to 600 meters, especially in the cool seas of the southern hemisphere, in South Africa, New Zealand and in the Southern Ocean , where they can be stock-forming. However, C. gracilis (Indo-Pacific) and C. indicus (Caribbean) also occur in shallow water (less than 20 m).
features
Like all wing gills, the Cephalodiscus species are worm-like animals only a few millimeters in size that inhabit self-produced tubes made of scleroprotein in colonies . They can be divided into head shield ( proboscis or protosoma ), collar ( mesosoma ) and trunk ( metasoma ). The head shield has a ventrally (downwards) directed, glandular adhesive disc with which the animals can crawl. Dorsally (above) on the collar there are usually nine pairs of lophophores (only one pair in Rhabdopleura ), which are covered with up to 50 ciliate tentacles arranged in two rows and which capture food particles ( filtration ). The sack-shaped trunk contains the U-shaped digestive tract and the simply built, paired gonads and ends in a long, retractable stem, which often ends in a disc-shaped widening with a suction cup. The mouth and gill slits are located on the collar, directly behind the adhesive disc, the anus on the opposite side behind the lophophores. The individual individuals of a Cephalodiscus colony are free; H. in contrast to Rhabdopleura, not connected by a stolon . They can also leave their living tube and crawl around freely, but usually remain anchored with the adhesive disk inside the tube. Cephalodiscus species grow up to 5 mm long (without a stem).
species
- Cephalodiscus agglutinans Harmer & Ridewood, 1914
- Cephalodiscus atlanticus Bayer, 1962
- Cephalodiscus australiensis Johnston & Muirhead, 1951
- Cephalodiscus calciformis Emig, 1977
- Cephalodiscus densus Andersson, 1907
- Cephalodiscus dodecalophus McIntosh, 1882
- Cephalodiscus evansi Ridewood
- Cephalodiscus fumosus John, 1932
- Cephalodiscus gilchristi Ridewood, 1908
- Cephalodiscus gracilis Harmer, 1905
- Cephalodiscus graptolitoides Dilly, 1993
- Cephalodiscus hodgsoni Ridewood, 1907
- Cephalodiscus indicus Schepotieff, 1909
- Cephalodiscus kempi John, 1932
- Cephalodiscus levinseni Harmer, 1905
- Cephalodiscus lutetianus Abrard, Dollfus & Soyer, 1950 †
- Cephalodiscus nigrescens Lankester, 1905
- Cephalodiscus sibogae Harmer, 1905
- Cephalodiscus solidus Andersson, 1907
literature
- Volker Storch , Ulrich Welsch : Systematic Zoology , Fischer, 1997, ISBN 3-437-25160-0
Web links
- Konikoff, C .; van der Land, J. (2013). Cephalodiscus M'Intosh, 1882 . In: Shenkar, N; Swalla, BJ; van der Land, J. (2013) Hemichordata World Database, World Register of Marine Species.