All known species live in a secreted coenecium attached to a rock substrate.[2] Unlike Rhabdopleura, Cephalodiscus species do not form large colonies and are only pseudocolonial, but they do share a common area with individual buds for each zooid.[2][3]Cephalodiscus zooids are also more mobile than their Rhabdopleura counterparts, and are able to move around within tubaria. Cephalodiscus zooids can be produced via asexual budding. There are a few pairs of tentacled arms, whereas Rhabdopleura has only one pair of arms.[3]
Speciesedit
19 living species of Cephalodiscus have been described:[4]
Proposed subgenera are idiothecia, demiothecia, orthoecus, and acoelothecia.[2]
Historical discoveryedit
The Cephalodisci are endemic to the Antarctic and Southern Ocean, whose relative inaccessibility has historically limited human study of the genus.[2] The Erebus and Terror may have unwittingly encountered C. Nigrescens specimens, and the ChallengerC. densus; but until the Swedish Antarctic Expedition of 1901-1903, only C. Dodecalphus had been identified.[5] In 1882, M'Intosh (later spelled McIntosh) had identified Dodecalphus from dredgedMagellanic-Straits material, work published 5 years later, but the discovery left cephalodiscid phylogeny unclear.[2][5] M'Intosh proposed placement amongst the polyzoa, whilst Harmer suggested the modern placement amongst hemichordates. The Swedish expedition provided a plethora of new species, and subsequent researchers began to recognize cephalodiscid species in the relatively temperate waters off South Africa, the Falklands, Sri Lanka, and Australia. At the same time, researchers also determined that C. rarus and andersonii were in fact C. densus specimens.[2]
^M'Intosh W (1882) Preliminary notice of Cephalodiscus, a new type allied to Prof. Allman's Rhabdopleura dredged in H.M.S. 'Challenger.'. Annals and Magazine of Natural History 10: 337-348
^ abcdefMarkham, John C. (1971). "The Species of Cephalodiscus collected during Operation Deep Freeze, 1956-1959". In Llano, George A.; Wallen, I. Eugene (eds.). Biology of the Antarctic Seas. Antarctic Research. Vol. 17 (IV). Baltimore: Horn-Shafer. pp. 83–110. ISBN0-87590-117-4 – via the Internet Archive.
^ abRidewood, W. G. (October 1921). "On specimens of Cephalodiscus densus dredged by the 'Challenger' in 1874 at Kerguelen Island" (PDF). Annals and Magazine of Natural History. 8 (46): 433–440. doi:10.1080/00222932108632603. ISSN 0374-5481 – via Biodiversity Heritage Library.
^Miyamoto N, Nishikawa T, Namikawa H (February 2020). "Cephalodiscus planitectus sp. nov. (Hemichordata: Pterobranchia) from Sagami Bay, Japan". Zoological Science. 37 (1): 79–90. doi:10.2108/zs190010. PMID 32068377. Retrieved 2020-09-17.
cephalodiscus, genus, hemichordates, monotypic, family, cephalodiscidae, order, cephalodiscida, dodecalophus, scientific, classification, kingdom, animalia, phylum, hemichordata, class, pterobranchia, order, cephalodiscida, family, cephalodiscidaeharmer, 1905,. Cephalodiscus is a genus of hemichordates in the monotypic family Cephalodiscidae of the order Cephalodiscida Cephalodiscus Cephalodiscus dodecalophus Scientific classification Kingdom Animalia Phylum Hemichordata Class Pterobranchia Order Cephalodiscida Family CephalodiscidaeHarmer 1905 Genus CephalodiscusM Intosh 1882 1 Type species Cephalodiscus dodecalophusMcIntosh 1882 Species See text Synonyms Demiothecia Ridewood 1906 Acoelothecia John 1931 Idiothecia Ridewood 1906 Orthoecus Andersson 1907 Contents 1 Description 2 Species 3 Historical discovery 4 References 5 External linksDescription editAll known species live in a secreted coenecium attached to a rock substrate 2 Unlike Rhabdopleura Cephalodiscus species do not form large colonies and are only pseudocolonial but they do share a common area with individual buds for each zooid 2 3 Cephalodiscus zooids are also more mobile than their Rhabdopleura counterparts and are able to move around within tubaria Cephalodiscus zooids can be produced via asexual budding There are a few pairs of tentacled arms whereas Rhabdopleura has only one pair of arms 3 Species edit19 living species of Cephalodiscus have been described 4 Cephalodiscus agglutinans Harmer amp Ridewood 1914 Cephalodiscus atlanticus Bayer 1962 Cephalodiscus australiensis Johnston amp Muirhead 1951 Cephalodiscus calciformis Emig 1977 Cephalodiscus densus Andersson 1907 Cephalodiscus rarus Andersson 1907 Cephalodiscus anderssoni Gravier 1912 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 aequatus Andersson 1907 Cephalodiscus inaequatus Andersson 1907 Cephalodiscus indicus Schepotieff 1909 Cephalodiscus kempi John 1932 Cephalodiscus levinsoni Harmer 1905 Cephalodiscus nigrescens Lankester 1905 Cephalodiscus planitectus Miyamoto Nishikawa and Namikawa 2020 Cephalodiscus sibogae Harmer 1905 Cephalodiscus solidus Andersson 1907 Extinct species include Cephalodiscus lutetianus Abrard Dollfus amp Soyer 1950 Cephalodiscus nusplingensis Schweigert amp Dietl 2013 Proposed subgenera are idiothecia demiothecia orthoecus and acoelothecia 2 Historical discovery editThe Cephalodisci are endemic to the Antarctic and Southern Ocean whose relative inaccessibility has historically limited human study of the genus 2 The Erebus and Terror may have unwittingly encountered C Nigrescens specimens and the Challenger C densus but until the Swedish Antarctic Expedition of 1901 1903 only C Dodecalphus had been identified 5 In 1882 M Intosh later spelled McIntosh had identified Dodecalphus from dredged Magellanic Straits material work published 5 years later but the discovery left cephalodiscid phylogeny unclear 2 5 M Intosh proposed placement amongst the polyzoa whilst Harmer suggested the modern placement amongst hemichordates The Swedish expedition provided a plethora of new species and subsequent researchers began to recognize cephalodiscid species in the relatively temperate waters off South Africa the Falklands Sri Lanka and Australia At the same time researchers also determined that C rarus and andersonii were in fact C densus specimens 2 Cephalodiscus planitectus is the most recently discovered species It was described in 2020 from specimens found in Sagami Bay off the southern coast of Honshu Japan 6 References edit M Intosh W 1882 Preliminary notice of Cephalodiscus a new type allied to Prof Allman s Rhabdopleura dredged in H M S Challenger Annals and Magazine of Natural History 10 337 348 a b c d e f Markham John C 1971 The Species of Cephalodiscus collected during Operation Deep Freeze 1956 1959 In Llano George A Wallen I Eugene eds Biology of the Antarctic Seas Antarctic Research Vol 17 IV Baltimore Horn Shafer pp 83 110 ISBN 0 87590 117 4 via the Internet Archive a b Maletz Jorg 2017 Graptolite Paleobiology Wiley Blackwell ISBN 9781118515617 Cephalodiscus WoRMS World Register of Marine Species a b Ridewood W G October 1921 On specimens of Cephalodiscus densus dredged by the Challenger in 1874 at Kerguelen Island PDF Annals and Magazine of Natural History 8 46 433 440 doi 10 1080 00222932108632603 ISSN 0374 5481 via Biodiversity Heritage Library Miyamoto N Nishikawa T Namikawa H February 2020 Cephalodiscus planitectus sp nov Hemichordata Pterobranchia from Sagami Bay Japan Zoological Science 37 1 79 90 doi 10 2108 zs190010 PMID 32068377 Retrieved 2020 09 17 External links edit nbsp Data related to Cephalodiscus at Wikispecies Cephalodiscus WoRMS World Register of Marine Species nbsp This hemichordate related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Cephalodiscus amp oldid 1186478565, wikipedia, wiki, book, books, library,
