Reef and Shore Polychaetes of Hawaii and the Western Pacific Islands

Magalhaes, Wagner
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[Honolulu] : [University of Hawaii at Manoa], [December 2015]
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Polychaete worms are one of the most successful groups of marine benthic invertebrates in terms of diversity of species, life styles, feeding modes and reproductive strategies. The polychaetes from the western Pacific Islands are scarcely known and the literature available for identification is outdated. A revision of the literature on Hawaii polychaete worms is presented in Chapter 1, together with a list of described species. In Chapter 2, an ecological study was performed in 16 sampling stations in the south shore of Oahu, ten stations were distributed in areas where an invasive alga occurred abundantly and six stations were placed on bare sand patches. Based on the comparison between Avrainvillea amadelpha-dominated bottoms and the surrounding bare sediment patches, our study demonstrates that these habitats support a diverse and abundant polychaete assemblage, with 2,621 individuals and 84 species collected. The possible effects of the presence of this invasive alga on the structure of the polychaete assemblages are discussed. A thorough taxonomic revision of six polychaete families occurring in Hawaii is presented in Chapter 3. The families Acrocirridae, Fauveliopsidae, Lacydoniidae, Poecilochaetidae, and Sphaerodoridae are new records to the Hawaiian marine fauna. A total of 24 species (7 of them new) are described in several papers organized by family. Chapter 4 aimed to review the Cirratulidae (including Ctenodrilidae) from the western Pacific (Hawaiian, Marshall, and Mariana Islands) and Eastern Atlantic oceans. Thirty species are fully described and illustrated, 17 of them are new. Chapter 5 includes a study on the feeding behavior and particle selection of a bitentaculate and a multitentaculate cirratulid species. The multitentaculate species studied was more successful in collecting particles from a greater area and at a faster rate than the bitentaculate species. This satisfied our expectations that feeding activities in multitentaculate species are more efficient than in bitentaculate species but a better understanding of the phylogenetic relationships between the bitentaculate and multitentaculate cirratulids was needed. In Chapter 6, a preliminary phylogeny was performed using morphological, anatomical and reproductive data of 11 cirratulid genera, four ctenodrilid genera and three outgroup genera. The dataset was analysed using Maximum Parsimony and Bayesian Inference. The family Cirratulidae is recovered in all analyses as monophyletic if all ctenodrilid genera are included within it. Three main clades are observed: i) the multitentaculate genera, ii) the bitentaculate genera and iii) the atentaculate genera. This new phylogenetic hypothesis and a better understanding of character evolution will provide information for several taxonomic improvements such as synonymization of Ctenodrilidae to Cirratulidae and revision of all generic diagnosis.
Ph.D. University of Hawaii at Manoa 2015.
Includes bibliographical references.
Polychaetes, Taxonomy, Ecology, Phylogeny, Feeding Biology
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Theses for the degree of Doctor of Philosophy (University of Hawaii at Manoa). Zoology
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