Phylogenetic relationships, morphological variation, and toxin patterns in the Alexandrium ostenfeldii (Dinophyceae) complex: implications for species boundaries and identities. Issue 1 (20th November 2013)

• Record Type: Journal Article
• Authors: Kremp, Anke; Tahvanainen, Pia; Litaker, Wayne; Krock, Bernd; Suikkanen, Sanna; Leaw, Chui Pin; Tomas, Carmelo; De Clerck, O.
• Is Part Of: Journal of phycology. Volume 50:Issue 1(2014:Feb.)
• Page Start: 81
• Page End: 100
• Publication Date: 2013-11-20
• Subjects: Algae -- Periodicals; 579.8
• DOI: 10.1111/jpy.12134
• Languages: English
• ISSNs: 0022-3646

Abstract

<abstract abstract-type="main" id="jpy12134-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <italic>Alexandrium ostenfeldii</italic> (Paulsen) Balech and Tangen and <italic>A. peruvianum</italic> (Balech and B.R. Mendiola) Balech and Tangen are morphologically closely related dinoflagellates known to produce potent neurotoxins. Together with <italic>Gonyaulax dimorpha</italic> Biecheler, they constitute the <italic>A. ostenfeldii</italic> species complex. Due to the subtle differences in the morphological characters used to differentiate these species, unambiguous species identification has proven problematic. To better understand the species boundaries within the <italic>A. ostenfeldii</italic> complex we compared rDNA data, morphometric characters and toxin profiles of multiple cultured isolates from different geographic regions. Phylogenetic analysis of rDNA sequences from cultures characterized as <italic>A. ostenfeldii</italic> or <italic>A. peruvianum</italic> formed a monophyletic clade consisting of six distinct groups. Each group examined contained strains morphologically identified as either <italic>A. ostenfeldii</italic> or <italic>A. peruvianum</italic>. Though key morphological characters were generally found to be highly variable and not consistently distributed, selected plate features and toxin profiles differed significantly among phylogenetic clusters. Additional sequence analyses revealed a lack of compensatory base changes in ITS2 rRNA structure, low to intermediate ITS/5.8S uncorrected genetic distances, and evidence of reticulation. Together these data (criteria currently used for species delineation in dinoflagellates) imply that the <italic>A. ostenfeldii</italic> complex should be regarded a single genetically structured species until more material and alternative criteria for species delimitation are available. Consequently, we propose that <italic>A. peruvianum</italic> is a heterotypic synonym of <italic>A. ostenfeldii</italic> and this taxon name should be discontinued.</p> </abstract>