title: TAXONOMIC REVISION OF SARGASSUM (FUCALES, PHAEOPHYCEAE) FROM FRENCH POLYNESIA BASED ON MORPHOLOGICAL AND MOLECULAR ANALYSES(1).
abstract: An assessment of Sargassum in French Polynesia was done through the critical revision of the literature, type specimens, and specimens from type localities. Sargassum samples were newly collected, and four morphotypes were identified on the basis of morphological characters. Molecular analysis of the nuclear ITS2, chloroplastic partial rbcLS, and mitochondrial cox3 markers generated two clades and confirmed the recent divergence suspected between closely related species. Although 18 different epithets have been attributed to French Polynesian Sargassum since 1828, only three species are considered valid in this study. Most of these species were transferred to S. pacificum Bory, the only species present in the Society Archipelago, while S. obtusifolium J. Agardh was restricted to the Austral Archipelago, and S. echinocarpum J. Agardh was confirmed for the Austral and Gambier Archipelagos. A morphological identification key is provided, along with descriptions and illustrations for each polymorphic species. Moreover, the study of several regional collections underlined similar and low specific diversity among Sargassum populations in the southeastern Pacific. As a result of this study, we propose that S. bacciferum J. Agardh var. latiuscula Grunow, S. bisserula f. pacifica Grunow, S. boraborense (Grunow) Setch., S. mangarevense (Grunow) Setch., S. sociale (Grunow) Setch., and S. tahitense Grunow be considered as heterotypic synonyms of S. pacificum. Sargassum skottsbergii Sjöstedt, S. hawaiiensis Doty et Newhouse, S. divaricatum var. chilensis Grunow, S. obtusifolium J. Agardh f. chamberlainii Grunow, and S. obtusifolium J. Agardh f. lendigeroides Grunow are further regarded as heterotypic synonyms of S. obtusifolium.
authors.affiliation: Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Méditerranée, UMR6540 DIMAR COM, 13288 Marseille cedex 9, France Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Polynésie Française, BP6570 Faa'a, Tahiti, French PolynesiaUniversité de Bretagne Occidentale, IUEM, LEBHAM EA 3877, 29280 Plouzané, France.
authors.forename: Lydiane
authors.initials: L
authors.lastname: Mattio
authors.affiliation: Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Méditerranée, UMR6540 DIMAR COM, 13288 Marseille cedex 9, France Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Polynésie Française, BP6570 Faa'a, Tahiti, French PolynesiaUniversité de Bretagne Occidentale, IUEM, LEBHAM EA 3877, 29280 Plouzané, France.
authors.forename: Claude Elisabeth
authors.initials: CE
authors.lastname: Payri
authors.affiliation: Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Méditerranée, UMR6540 DIMAR COM, 13288 Marseille cedex 9, France Institut de Recherche pour le Développement, UMR7138 SAE, BPA5, 98848 Nouméa, New Caledonia Université de la Polynésie Française, BP6570 Faa'a, Tahiti, French PolynesiaUniversité de Bretagne Occidentale, IUEM, LEBHAM EA 3877, 29280 Plouzané, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Stiger-Pouvreau
keywords: French Polynesia; ITS2; Sargassum; biogeography; cox3; molecular phylogeny; rbcLS; taxonomic revision