title: Formal revision of the Alexandrium tamarense species complex (Dinophyceae) taxonomy: the introduction of five species with emphasis on molecular-based (rDNA) classification.
abstract: The Alexandrium tamarense species complex is one of the most studied marine dinoflagellate groups due to its ecological, toxicological and economic importance. Several members of this complex produce saxitoxin and its congeners - potent neurotoxins that cause paralytic shellfish poisoning. Isolates from this complex are assigned to A. tamarense, A. fundyense, or A. catenella based on two main morphological characters: the ability to form chains and the presence/absence of a ventral pore between Plates 1' and 4'. However, studies have shown that these characters are not consistent and/or distinctive. Further, phylogenies based on multiple regions in the rDNA operon indicate that the sequences from morphologically indistinguishable isolates partition into five clades. These clades were initially named based on their presumed geographic distribution, but recently were renamed as Groups I-V following the discovery of sympatry among some groups. In this study we present data on morphology, ITS/5.8S genetic distances, ITS2 compensatory base changes, mating incompatibilities, toxicity, the sxtA toxin synthesis gene, and rDNA phylogenies. All results were consistent with each group representing a distinct cryptic species. Accordingly, the groups were assigned species names as follows: Group I, A. fundyense; Group II, A. mediterraneum; Group III, A. tamarense; Group IV, A. pacificum; Group V, A. australiense.
authors.affiliation: Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany. Electronic address: uwe.john@awi.de.
authors.forename: Uwe
authors.initials: U
authors.lastname: John
authors.affiliation: National Oceanic and Atmospheric Administration, National Ocean Service, National Centers for Coastal Oceans Science, Center for Fisheries and Habitat Research, 101 Pivers Island Road, Beaufort, North Carolina 28516, United States.
authors.forename: R Wayne
authors.initials: RW
authors.lastname: Litaker
authors.affiliation: Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Montresor
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, PO Box 123 Broadway, NSW 2007, Australia.
authors.forename: Shauna
authors.initials: S
authors.lastname: Murray
authors.affiliation: Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, United States.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Brosnahan
authors.affiliation: Woods Hole Oceanographic Institution, MS # 32, 266 Woods Hole Road, Woods Hole, Massachusetts 02543, United States.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Anderson
mesh_terms: D004275:DNA, Ribosomal / Q000235:genetics*; D030541:Databases, Genetic; D004141:Dinoflagellida / Q000145:classification* / Q000235:genetics*; D005819:Genetic Markers; D008387:Marine Toxins / Q000737:chemistry; D009498:Neurotoxins / Q000737:chemistry; D010802:Phylogeny; D012530:Saxitoxin / Q000737:chemistry; D013045:Species Specificity
chemical_list: D004275:DNA, Ribosomal; D005819:Genetic Markers; D008387:Marine Toxins; D009498:Neurotoxins; D012530:Saxitoxin
keywords: Alexandrium australiense.; Alexandrium fundyense; Alexandrium mediterraneum; Alexandrium pacificum; Alexandrium tamarense