| The internal-brooding apparatus in the bryozoan genus Cauloramphus (Cheilostomata: Calloporidae) and its inferred homology to ovicells. | |
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MedLine Citation:
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PMID: 18271635 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We studied by SEM the external morphology of the ooecium in eight bryozoans of the genus Cauloramphus (Cheilostomata, Calloporidae): C. spinifer, C. variegatus, C. magnus, C. multiavicularia, C. tortilis, C. cryptoarmatus, C. niger, and C. multispinosus, and by sectioning and light microscopy the anatomy of the brooding apparatus of C. spinifer, C. cryptoarmatus, and C. niger. These species all have a brood sac, formed by invagination of the non-calcified distal body wall of the maternal zooid, located in the distal half of the maternal (egg-producing) autozooid, and a vestigial, maternally budded kenozooidal ooecium. The brood sac comprises a main chamber and a long passage (neck) opening externally independently of the introvert. The non-calcified portion of the maternal distal wall between the neck and tip of the zooidal operculum is involved in closing and opening the brood sac, and contains both musculature and a reduced sclerite that suggest homology with the ooecial vesicle of a hyperstomial ovicell. We interpret the brooding apparatus in Cauloramphus as a highly modified form of cheilostome hyperstomial ovicell, as both types share 1) a brood chamber bounded by 2) the ooecium and 3) a component of the distal wall of the maternal zooid. We discuss Cauloramphus as a hypothetical penultimate stage in ovicell reduction in calloporid bryozoans. We suggest that the internal-brooding genus Gontarella, of uncertain taxonomic affinities, is actually a calloporid and represents the ultimate stage in which no trace of the ooecium remains. Internal brooding apparently evolved several times independently within the Calloporidae. |
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Authors:
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Andrew N Ostrovsky; Matthew H Dick; Shunsuke F Mawatari |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Zoological science Volume: 24 ISSN: 0289-0003 ISO Abbreviation: Zool. Sci. Publication Date: 2007 Dec |
Date Detail:
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Created Date: 2008-02-14 Completed Date: 2008-06-30 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8702287 Medline TA: Zoolog Sci Country: Japan |
Other Details:
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Languages: eng Pagination: 1187-96 Citation Subset: IM |
Affiliation:
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Department of Invertebrate Zoology, Faculty of Biology & Soil Science, St. Petersburg State University, Universitetskaja nab. 7/9, St. Petersburg 199034, Russia. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Bryozoa / anatomy & histology*, embryology, ultrastructure* Embryonic Development* Evolution, Molecular* Female Male Microscopy, Electron, Scanning / methods, veterinary* Oviposition / physiology Species Specificity |
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