![]() | Genetic diversity of the harmful family Kareniaceae (Gymnodiniales, Dinophyceae) in France, with the description of Karlodinium gentienii sp. nov.: A new potentially toxic dinoflagellate Auteur(s) : Nezan, Elisabeth Siano, Raffaele Boulben, Sylviane Six, Christophe Bilien, Gwenael Cheze, Karine Duval, Audrey Le Panse, Sophie Éditeur(s) : Elsevier Résumé : The family Kareniaceae is mostly known in France for recurrent blooms of Karenia mikimotoi in the Atlantic, English Channel, and Mediterranean Sea and for the unusual green discoloration in the saltwater lagoon of Diana (Corsica) caused by Karlodinium corsicum in April 1994. In terms of diversity, this taxonomic group was long overlooked owing to the difficult identification of these small unarmored dinoflagellates. In this study, thanks to the molecular characterization performed on single cells from field samples and cultures, twelve taxonomic units were assigned to the known genera Karenia, Karlodinium and Takayama, whereas one could not be affiliated to any described genus. The molecular phylogeny inferred from the D1–D2 region of the LSU rDNA showed that five of them formed a sister taxon of a known species, and could not be identified at species-level, on the basis of molecular analysis only. Among these latter taxa, one Karlodinium which was successfully cultured was investigated by studying the external morphological features (using two procedures for cells fixation), ultrastructure, pigment composition, and haemolytic activity. The results of our analyses corroborate the genetic results in favour of the erection of Karlodinium gentienii sp. nov., which possesses an internal complex system of trichocysts connected to external micro-processes particularly abundant in the epicone, and a peculiar pigment composition. In addition, preliminary assays showed a haemolytic activity. Harmful Algae (1568-9883) (Elsevier), 2014-12 , Vol. 40 , P. 75-91 Droits : 2014 Elsevier B.V. All rights reserved. http://archimer.ifremer.fr/doc/00225/33611/32310.pdf DOI:10.1016/j.hal.2014.10.006 http://archimer.ifremer.fr/doc/00225/33611/ | Partager |
![]() | Madanidinium loirii gen. et sp nov. (Dinophyceae), a new marine benthic dinoflagellate from Martinique Island, Eastern Caribbean Auteur(s) : Chomerat, Nicolas Bilien, Gwenael Éditeur(s) : Taylor & Francis Ltd Résumé : A new benthic phototrophic dinoflagellate is described from sediments of a tropical marine cove at Martinique Island and its micromorphology is studied by means of light and electron microscopy. The cell contains small golden-brown chloroplasts and the oval nucleus is posterior. It is laterally compressed, almost circular in shape when viewed laterally. It consists of a small epitheca tilted toward the right lateral side and a larger hypotheca. In the left view, the cingulum is more anterior and the epitheca is reduced. The cingulum is displaced and left-handed. This organism is peculiar in having no apical pore and its thecal plate arrangement is 2 ' 1a 7 '' 5c 3s 5 ''' 1 ''''. The plates are smooth with small groups of pores scattered on their surface. An area with 60-80 densely arranged pores is found near the centre of the 2 ''' plate, on the left lateral side. Morphologically, these features are different from all other laterally compressed benthic genera. In addition, molecular genetic sequences of SSU and partial LSU form a distinct and well-supported clade among dinoflagellates and support the erection of a new genus. However, molecular phylogenies inferred from ribosomal genes failed to confirm any clear relationship with other benthic taxa and affinity with other laterally compressed dinoflagellates has not been demonstrated. Hence, the taxonomic affinity of Madanidinium loirii with a defined order and family is unclear at the moment. European Journal Of Phycology (0967-0262) (Taylor & Francis Ltd), 2014-04 , Vol. 49 , N. 2 , P. 165-178 Droits : 2014 British Phycological Society http://archimer.ifremer.fr/doc/00195/30622/29458.pdf DOI:10.1080/09670262.2014.898797 http://archimer.ifremer.fr/doc/00195/30622/ | Partager |
![]() | Morphology and molecular phylogeny of prorocentrum consutum sp. nov. (dinophyceae), a new benthic dinoflagellate from south Brittany (northwestern France) Auteur(s) : Chomerat, Nicolas Sellos, Daniel Y. Zentz, Frederic Nezan, Elisabeth Éditeur(s) : Wiley / Blackwell Résumé : A new marine benthic Prorocentrum species from sandy habitats of South Brittany (northwestern France), P. consutum sp. nov., is described using LM and SEM and molecular phylogenetic analyses. Cells have a subcircular to broadly ovoid shape and are plainly flattened. They are 57-61 lm long and 52-55 lm wide. A central pyrenoid is present, and the kidney-shaped nucleus is positioned in the posterior region. In right valve view, the periflagellar area is deeply excavated, and the left valve forms a prominent apical ridge. The periflagellar area consists of nine platelets, and a small narrow collar is present around the flagellar pore. The ornamentation of this new species is very peculiar and is characterized by a ring of round areolae located at the periphery of the valves, each areola containing three or four pores. Apart from this ring of areolae, the cell surface is smooth and with scattered pores. Pores are not present in the center of the right or left valve. The intercalary band is generally narrow and faintly striated horizontally. The molecular phylogenetic position of P. consutum sp. nov. was inferred using SSU and LSU rDNA. In both analyses, this species branched with high support in the clade comprising species with a symmetric shape and appeared to be a sister group to that formed by P. lima and other tropical benthic species, such as P. arenarium, P. belizeanum, P. hoffmannianum, and P. maculosum. Journal of Phycology (0022-3646) (Wiley / Blackwell), 2010-02 , Vol. 46 , N. 1 , P. 183-194 Droits : 2010 Wiley Blackwell Publishing, Inc. Phycological Society of America http://archimer.ifremer.fr/doc/2010/publication-7449.pdf DOI:10.1111/j.1529-8817.2009.00774.x http://archimer.ifremer.fr/doc/00000/7449/ | Partager Voir aussi Taxonomy SSU rDNA SEM Prorocentrum Nuclear DNA Molecular phylogeny LSU rDNA Dinoflagellates Télécharger |
![]() | Prorocentrum bimaculatum sp nov (Dinophyceae, prorocentrales), a new benthic dinoflagellate species from Kuwait (Arabian gulf) Auteur(s) : Chomerat, Nicolas Saburova, Maria Bilien, Gwenael Al-yamani, Faiza Éditeur(s) : Wiley-blackwell Résumé : A new benthic dinoflagellate species, Prorocentrum bimaculatum sp. nov., is studied from Kuwaits marine sediments, based on detailed morphological and molecular data. Cells are large, oblong oval in shape. They are 49.955.3 mu m long and 38.443.2 mu m wide. The ornamentation of this new species is peculiar, and characterized by smooth valves with large pores (0.320.50 mu m) scattered on their surface, except in two circular patches of similar to 15 mu m in diameter, devoid of ornamentation and located on both sides of the valve centers. The periflagellar area is widely triangular, located in a moderate excavation of the right valve, and comprises nine platelets. The intercalary band of P. bimaculatum is smooth. The molecular phylogenetic position of this new taxon was inferred from SSU and LSU rDNA genes. In both phylogenetic analyses, P. bimaculatum branched with high support with Prorocentrum consutum and formed a clade sister to the one including P. lima and related species such as P. arenarium, P. belizeanum, P. hoffmannianum, and P. maculosum. From the phylogenetic study, since most species related to P. bimaculatum are known for their toxic effects and production of okadaic acid, this new species can be considered as a potential toxin producer, but this has to be analyzed. Journal Of Phycology (0022-3646) (Wiley-blackwell), 2012-02 , Vol. 48 , N. 1 , P. 211-221 Droits : 2012 Phycological Society of America http://archimer.ifremer.fr/doc/00066/17756/15698.pdf DOI:10.1111/j.1529-8817.2011.01102.x http://archimer.ifremer.fr/doc/00066/17756/ | Partager Voir aussi Arabian Gulf benthic dinoflagellates Kuwait molecular phylogeny morphology nuclear DNA Prorocentrum rDNA SEM taxonomy Télécharger |