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Publication Type
Journal Article
UWI Author(s)
Author, Analytic
Donovan, S.K.
Author Affiliation, Ana.
Geography and Geology; Faculty of Pure and Applied Sciences
Article Title
Contractile tissues in the cirri of ancient crinoids: Criteria for recognition.
Medium Designator
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Connective Phrase
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Journal Title
Lethaia
Translated Title
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Reprint Status
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Date of Publication
1993
Volume ID
26
Issue ID
2
Page(s)
163-169
Language
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Connective Phrase
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Location/URL
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ISSN
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Notes
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Abstract
Stalked isocrinid and 'stalkless' comatulid crinoids are able to relocate by crawling on or swimming with their muscular arms. Reattachment is achieved using cirri containing contractile tissues that produce aboral flexure. The following cirral adaptations for active attachment were observed during a SEM study of two comasterid comatulids, Davidaster rubiginosa (Pourtales) and D.discoidea (Carpenter): synarthrial articulations; fulcral ridges corresponding to short axes of ossicles; cirri flattened laterally; each cirrus with a claw at the tip and an aboral attachment pad; cirri serrated aborally and distally. Epizoans are only able to encrust single ossicles in actively motile cirri. These adaptations are associated with crinoids with muscular arms that are used in relocation. Such a suite of characters is unknown in Palaeozoic crinoids; the ability to relocate evolved in crinoids only during the Mesozoic.....
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Keywords
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