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Life cycle evolution and systematics of Campanulariid hydrozoans

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dc.contributor.advisor Laurence P. Madin. en_US Govindarajan, Annette Frese, 1970- en_US
dc.contributor.other Joint Program in Oceanography/Applied Ocean Science and Engineering. en_US 2007-10-22T19:53:20Z 2007-10-22T19:53:20Z 2004 en_US 2004 en_US
dc.description Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and, the Woods Hole Oceanographic Institution), 2004. en_US
dc.description Includes bibliographical references. en_US
dc.description.abstract The purpose of this thesis is to study campanulariid life cycle evolution and systematics. The Campanulariidae is a hydrozoan family with many life cycle variations, and provide an excellent model system to study life cycle evolution. Additionally, the unique campanulariid Obelia medusae may have been "re-invented" from ancestors without medusae. Chapter 1 reviews campanulariid life cycles and taxonomy. Chapter 2 presents a phylogeny based on 18S rDNA, calmodulin, 16S rDNA and cytochrome c oxidase I (COI). Ancestral life cycles are reconstructed using parsimony. Medusa loss is common, and Obelia may derive from ancestors with typical medusae. Taxonomic results are discussed in Chapter 3. Billardia, a nominal campanulariid, appears phylogenetically distant, while Bonneviella spp. (Bonneviellidae), are nested within the Campanulariidae. Campanulariid genera are not monophyletic. Orthopyxis integra and Clytia gracilis may represent cryptic species, while Obelia longissima may be cosmopolitan. Chapter 4 investigates Obelia geniculata phylogeography. Japanese and North Atlantic 16S rDNA and COI sequences are calibrated against the opening of the Bering Strait. Substitution rates are faster than in anthozoans and comparable to non-cnidarian invertebrates. Comparison of Pacific and Atlantic sequences suggests cryptic species exist. Finally, hydroids in New Brunswick, Canada and Iceland may have survived the last glaciation. en_US
dc.description.statementofresponsibility by Annette Frese Govindarajan. en_US
dc.format.extent 180 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.subject Biology. en_US
dc.subject Woods Hole Oceanographic Institution. en_US
dc.subject /Woods Hole Oceanographic Institution. Joint Program in Oceanography/Applied Ocean Science and Engineering. en_US
dc.title Life cycle evolution and systematics of Campanulariid hydrozoans en_US
dc.type Thesis en_US Ph.D. en_US
dc.contributor.department Massachusetts Institute of Technology. Dept. of Biology. en_US
dc.contributor.department Woods Hole Oceanographic Institution. en_US
dc.contributor.department Joint Program in Oceanography/Applied Ocean Science and Engineering. en_US
dc.identifier.oclc 58995712 en_US

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