Morphology, phylogeny and taxonomy of species within the Pseudo-nitzschia americana complex (Bacillariophyceae) with descriptions of two new species, Pseudo-nitzschia brasiliana and Pseudo-nitzschia…

By Nina Lundholm, G. Hasle, G. Fryxell, P. Hargraves. 2002

128 citations recorded by the source corpus.

Abstract Pseudo-nitzschia americana and the two closely related species P. brasiliana Lundholm, Hasle & G.A. Fryxell sp. nov. and P. linea Lundholm, Hasle & G.A. Fryxell sp. nov. are described, based on morphology. The phylogenetic positions of P. americana and P. brasiliana are inferred from partial nuclear-encoded large-subunit ribosomal DNA and their toxin production is assessed. The new species P. brasiliana and P. linea form stepped colonies, whereas P. americana is single celled. Pseudo-nitzschia americana, P. brasiliana and P. linea possess morphological features typical of Pseudo-nitzschia and Fragilariopsis, differentiating them from Nitzschia. All three species possess valve shapes similar to many Fragilariopsis species and they seem to constitute a morphological continuum between Pseudo-nitzschia and Fragilariopsis. Molecular phylogenetic analyses showed P. americana and P. brasiliana to be sister taxa within a strongly supported monophyletic clade comprising Pseudo-nitzschia and Fragilariopsis. On the basis of both the morphological and phylogenetic results, we conclude that P. americana can be assigned to Pseudo-nitzschia, following previous uncertainty as to whether it might belong to Nitzschia. Both P. americana and P. linea have been observed as epiphytes on other diatoms, which might indicate physiological differences from P. brasiliana, which has only been found free-living. In addition, P. americana and P. brasiliana differ with respect to valve width (transapical axis), the density of the transapical ribs (interstriae) and fibulae and the structure of the girdle bands (copulae). The results of the phylogenetic analyses and differences in distribution support these morphological differences. Pseudo-nitzschia linea differs with respect to valve shape, density of interstriae and structure of the girdle bands.

Subfields: Biomaterials, Environmental Chemistry

View Paper: https://www.semanticscholar.org/paper/b552bf045a153eaec6be17721826a515d79fee60

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Citations in the corpus

EFFECT OF SALINITY ON PSEUDO‐NITZSCHIA SPECIES (BACILLARIOPHYCEAE) GROWTH AND DISTRIBUTION 1 (2005, background): “The first four of these are known toxin producers somewhere in the world (Bates et al. 1998, Lundholm et al. 2002, Fryxell and Hasle 2003).”
Distribution of the cyanobacterium Richelia intracellularis as an epiphyte of the diatom Chaetoceros compressus in the western Pacific Ocean (2005, background): “Later, Lemmermann ( Lemmermann, 1905 ) reported C. rhizosoleniae to occur as an endosymbiont in Rhizosolenia and Hemiaulus and as an epiphyte on Chaetoceros .C arpenter (Carpenter, 2002) used the name Calothrix for a cyanobacterium found growing epiphytically on Chaetoceros ,a s opposed to the name ”
The Ecology of Harmful Diatoms (2006, background): “Coastal species that have not been shown to produce DA include P. americana (Villac et al. 1993), P. brasiliana ( Lundholm et al. 2002b ), and P. cf. subpacifica (Lundholm et al. 2002a); several other species have not yet been tested.”
Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health (2012, methodology): “Different regions of the genome have been targeted to assess the phylogeny of Pseudo-nitzschia : LSU, ITS1, 5.8S and ITS2 of the ribosomal DNA and rbcL, the large subunit of RuBisCo (Lundholm et al., 2002a,b, 2006; Orsini et al., 2004; Amato et al., 2007).”
Pseudo-nitzschia (Bacillariophyceae) species, domoic acid and amnesic shellfish poisoning: revisiting previous paradigms (2012, background): “…et al. 2002b; QuijanoScheggia et al. 2010) as single cells on Chaetoceros and Odontella spp. colonies; P. delicatissima as single cells in Phaeocystis colonies (Lundholm et al. 2002a; Sazhin et al. 2007); and P. cf. granii var. curvata in Phaeocystis pouchetii colonies (Sazhin et al. 2007).”
LIFE CYCLE, SIZE REDUCTION PATTERNS, AND ULTRASTRUCTURE OF THE PENNATE PLANKTONIC DIATOM PSEUDO‐NITZSCHIA DELICATISSIMA (BACILLARIOPHYCEAE) 1 (2005, background): “…self-fertilization or conjugation within strains of the same mating type cannot be ruled out for all species of Pseudo-nitzschia, because longer cells were observed in a culture of P. brasiliana Lundholm, Hasle and Fryxell, in which most cells had reached the minimum size (Lundholm et al. 2002a).”