title: TAXONOMIC REVISION OF THE DINOFLAGELLATE AMPHIDOMA CAUDATA: TRANSFER TO THE GENUS AZADINIUM (DINOPHYCEAE) AND PROPOSAL OF TWO VARIETIES, BASED ON MORPHOLOGICAL AND MOLECULAR PHYLOGENETIC ANALYSES(1).
abstract: The systematic position of Amphidoma caudata Halldal within the genus Amphidoma has remained uncertain as a result of its plate formula and the absence of molecular phylogenetic data. Also, this thecate dinoflagellate taxon has been used to designate two distinct morphotypes. The present study aims to clarify the generic affiliation of Amphidoma caudata and the taxonomic value of two different morphotypes M1 and M2. The new examination of the plate formula using SEM showed that it was the same for both morphotypes and that it corresponded to the tabulation of the recent erected genus Azadinium Elbrächter et Tillmann. Morphometric analysis, using cell size, length of apical projection in conjunction with the cell length, and the ratio of horn and spine showed that M1 and M2 formed two distinct groups. These results were supported by a molecular approach, revealing notable differences in the sequences of LSU rDNA and ITS region between these two morphotypes. Phylogenetic analyses inferred either from LSU and combined SSU, ITS region and COI data positioned M1 and M2 in a sister cluster of Azadinium species while Amphidoma languida Tillmann, Salas et Elbrächter, the only species of Amphidoma for which sequence data were available, was situated in a basal position of the Azadinium clade. Thus, we propose the transfer of Amphidoma caudata to the genus Azadinium and, consequently, the rehabilitation of the original tabulation of the genus Amphidoma Stein. To discriminate the two morphotypes, we propose a rank of variety with the following designations: Azadinium caudatum var. caudatum and Azadinium caudatum var. margalefii.
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Nézan
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Urban
authors.initials: U
authors.lastname: Tillmann
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Gwenae L
authors.initials: GL
authors.lastname: Bilien
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Boulben
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Chèze
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Zentz
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Rafael
authors.initials: R
authors.lastname: Salas
authors.affiliation: Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceAlfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, FranceMuséum National d'Histoire Naturelle, Station de Biologie Marine, B.P. 225, 29182 Concarneau Cedex, FranceUniversité de Bretagne Occidentale, Institut Universitaire de Technologie, 2 rue de l'Université, 29334 Quimper Cedex, FranceMarine Institute, Rinville Oranmore, Galway, Ireland Ifremer, Laboratoire Environnement et Ressources Finistère-Bretagne Nord, Station de biologie marine, Place de la Croix, BP 40537, 29185 Concarneau Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chomérat
keywords: Amphidoma caudata; Amphidomataceae; Azadinium; SEM; morphology; phylogeny; taxonomy; thecate dinoflagellates